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EUVD-2026-346537

European Vulnerability Database identifier assigned by ENISA

Reserved

2026-10-02 08:09

Assigner

ENISA

Alias of

a CVE record, shown under related vulnerabilities. This identifier carries no description, severity or references of its own: they belong to that CVE.

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{
  "assigner": "ENISA",
  "date_reserved": "2026-10-02T08:09:44.433812+00:00",
  "id": "EUVD-2026-346537"
}

CVE-2024-56779 (GCVE-0-2024-56779)

Vulnerability from cvelistv5 – Published: 2025-01-08 17:49 – Updated: 2026-08-05 11:46

Title

nfsd: fix nfs4_openowner leak when concurrent nfsd4_open occur

Summary

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix nfs4_openowner leak when concurrent nfsd4_open occur The action force umount(umount -f) will attempt to kill all rpc_task even umount operation may ultimately fail if some files remain open. Consequently, if an action attempts to open a file, it can potentially send two rpc_task to nfs server. NFS CLIENT thread1 thread2 open("file") ... nfs4_do_open _nfs4_do_open _nfs4_open_and_get_state _nfs4_proc_open nfs4_run_open_task /* rpc_task1 */ rpc_run_task rpc_wait_for_completion_task umount -f nfs_umount_begin rpc_killall_tasks rpc_signal_task rpc_task1 been wakeup and return -512 _nfs4_do_open // while loop ... nfs4_run_open_task /* rpc_task2 */ rpc_run_task rpc_wait_for_completion_task While processing an open request, nfsd will first attempt to find or allocate an nfs4_openowner. If it finds an nfs4_openowner that is not marked as NFS4_OO_CONFIRMED, this nfs4_openowner will released. Since two rpc_task can attempt to open the same file simultaneously from the client to server, and because two instances of nfsd can run concurrently, this situation can lead to lots of memory leak. Additionally, when we echo 0 to /proc/fs/nfsd/threads, warning will be triggered. NFS SERVER nfsd1 nfsd2 echo 0 > /proc/fs/nfsd/threads nfsd4_open nfsd4_process_open1 find_or_alloc_open_stateowner // alloc oo1, stateid1 nfsd4_open nfsd4_process_open1 find_or_alloc_open_stateowner // find oo1, without NFS4_OO_CONFIRMED release_openowner unhash_openowner_locked list_del_init(&oo->oo_perclient) // cannot find this oo // from client, LEAK!!! alloc_stateowner // alloc oo2 nfsd4_process_open2 init_open_stateid // associate oo1 // with stateid1, stateid1 LEAK!!! nfs4_get_vfs_file // alloc nfsd_file1 and nfsd_file_mark1 // all LEAK!!! nfsd4_process_open2 ... write_threads ... nfsd_destroy_serv nfsd_shutdown_net nfs4_state_shutdown_net nfs4_state_destroy_net destroy_client __destroy_client // won't find oo1!!! nfsd_shutdown_generic nfsd_file_cache_shutdown kmem_cache_destroy for nfsd_file_slab and nfsd_file_mark_slab // bark since nfsd_file1 // and nfsd_file_mark1 // still alive ======================================================================= BUG nfsd_file (Not tainted): Objects remaining in nfsd_file on __kmem_cache_shutdown() ----------------------------------------------------------------------- Slab 0xffd4000004438a80 objects=34 used=1 fp=0xff11000110e2ad28 flags=0x17ffffc0000240(workingset|head|node=0|zone=2|lastcpupid=0x1fffff) CPU: 4 UID: 0 PID: 757 Comm: sh Not tainted 6.12.0-rc6+ #19 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 Call Trace: <TASK> dum ---truncated---

Severity

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

5.5 (Medium)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-10-01 19:56 UTC

CWE

CWE-401 - Missing Release of Memory after Effective Lifetime

Assigner

Linux mitre root Scorecard

References

9 references

URL	Tags
https://git.kernel.org/stable/c/a85364f0d30dee01c…
https://git.kernel.org/stable/c/2d505a801e5742805…
https://git.kernel.org/stable/c/0ab0a3ad24e970e89…
https://git.kernel.org/stable/c/45abb68c941ebc9a3…
https://git.kernel.org/stable/c/37dfc81266d3a3229…
https://git.kernel.org/stable/c/6f73f920b7ad00843…
https://git.kernel.org/stable/c/98100e88dd8865999…
https://lists.debian.org/debian-lts-announce/2025…
https://lists.debian.org/debian-lts-announce/2025…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 3234975f477f746c22d076ea178a79ea104b2ca7 , < a85364f0d30dee01c5d5b4afa55a9629a8f36d8e (git) Affected: 3234975f477f746c22d076ea178a79ea104b2ca7 , < 2d505a801e57428057563762f67a5a62009b2600 (git) Affected: 3234975f477f746c22d076ea178a79ea104b2ca7 , < 0ab0a3ad24e970e894abcac58f85c332d1726749 (git) Affected: 3234975f477f746c22d076ea178a79ea104b2ca7 , < 45abb68c941ebc9a35c6d3a7b08196712093c636 (git) Affected: 3234975f477f746c22d076ea178a79ea104b2ca7 , < 37dfc81266d3a32294524bfadd3396614f8633ee (git) Affected: 3234975f477f746c22d076ea178a79ea104b2ca7 , < 6f73f920b7ad0084373e46121d7ac34117aed652 (git) Affected: 3234975f477f746c22d076ea178a79ea104b2ca7 , < 98100e88dd8865999dc6379a3356cd799795fe7b (git)
Linux	Linux	Affected: 3.17 Unaffected: 0 , < 3.17 (semver) Unaffected: 5.4.287 , ≤ 5.4.* (semver) Unaffected: 5.10.231 , ≤ 5.10.* (semver) Unaffected: 5.15.174 , ≤ 5.15.* (semver) Unaffected: 6.1.120 , ≤ 6.1.* (semver) Unaffected: 6.6.64 , ≤ 6.6.* (semver) Unaffected: 6.12.4 , ≤ 6.12.* (semver) Unaffected: 6.13 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 5.5,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2024-56779",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-10-01T19:56:28.713212Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-401",
                "description": "CWE-401 Missing Release of Memory after Effective Lifetime",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-10-01T19:57:24.125Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-03T20:54:16.750Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html"
          },
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a85364f0d30dee01c5d5b4afa55a9629a8f36d8e",
              "status": "affected",
              "version": "3234975f477f746c22d076ea178a79ea104b2ca7",
              "versionType": "git"
            },
            {
              "lessThan": "2d505a801e57428057563762f67a5a62009b2600",
              "status": "affected",
              "version": "3234975f477f746c22d076ea178a79ea104b2ca7",
              "versionType": "git"
            },
            {
              "lessThan": "0ab0a3ad24e970e894abcac58f85c332d1726749",
              "status": "affected",
              "version": "3234975f477f746c22d076ea178a79ea104b2ca7",
              "versionType": "git"
            },
            {
              "lessThan": "45abb68c941ebc9a35c6d3a7b08196712093c636",
              "status": "affected",
              "version": "3234975f477f746c22d076ea178a79ea104b2ca7",
              "versionType": "git"
            },
            {
              "lessThan": "37dfc81266d3a32294524bfadd3396614f8633ee",
              "status": "affected",
              "version": "3234975f477f746c22d076ea178a79ea104b2ca7",
              "versionType": "git"
            },
            {
              "lessThan": "6f73f920b7ad0084373e46121d7ac34117aed652",
              "status": "affected",
              "version": "3234975f477f746c22d076ea178a79ea104b2ca7",
              "versionType": "git"
            },
            {
              "lessThan": "98100e88dd8865999dc6379a3356cd799795fe7b",
              "status": "affected",
              "version": "3234975f477f746c22d076ea178a79ea104b2ca7",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.17"
            },
            {
              "lessThan": "3.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.4.*",
              "status": "unaffected",
              "version": "5.4.287",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.231",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.174",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.120",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.64",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.13",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.4.287",
                  "versionStartIncluding": "3.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.231",
                  "versionStartIncluding": "3.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.174",
                  "versionStartIncluding": "3.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.120",
                  "versionStartIncluding": "3.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.64",
                  "versionStartIncluding": "3.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.4",
                  "versionStartIncluding": "3.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.13",
                  "versionStartIncluding": "3.17",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix nfs4_openowner leak when concurrent nfsd4_open occur\n\nThe action force umount(umount -f) will attempt to kill all rpc_task even\numount operation may ultimately fail if some files remain open.\nConsequently, if an action attempts to open a file, it can potentially\nsend two rpc_task to nfs server.\n\n                   NFS CLIENT\nthread1                             thread2\nopen(\"file\")\n...\nnfs4_do_open\n _nfs4_do_open\n  _nfs4_open_and_get_state\n   _nfs4_proc_open\n    nfs4_run_open_task\n     /* rpc_task1 */\n     rpc_run_task\n     rpc_wait_for_completion_task\n\n                                    umount -f\n                                    nfs_umount_begin\n                                     rpc_killall_tasks\n                                      rpc_signal_task\n     rpc_task1 been wakeup\n     and return -512\n _nfs4_do_open // while loop\n    ...\n    nfs4_run_open_task\n     /* rpc_task2 */\n     rpc_run_task\n     rpc_wait_for_completion_task\n\nWhile processing an open request, nfsd will first attempt to find or\nallocate an nfs4_openowner. If it finds an nfs4_openowner that is not\nmarked as NFS4_OO_CONFIRMED, this nfs4_openowner will released. Since\ntwo rpc_task can attempt to open the same file simultaneously from the\nclient to server, and because two instances of nfsd can run\nconcurrently, this situation can lead to lots of memory leak.\nAdditionally, when we echo 0 to /proc/fs/nfsd/threads, warning will be\ntriggered.\n\n                    NFS SERVER\nnfsd1                  nfsd2       echo 0 \u003e /proc/fs/nfsd/threads\n\nnfsd4_open\n nfsd4_process_open1\n  find_or_alloc_open_stateowner\n   // alloc oo1, stateid1\n                       nfsd4_open\n                        nfsd4_process_open1\n                        find_or_alloc_open_stateowner\n                        // find oo1, without NFS4_OO_CONFIRMED\n                         release_openowner\n                          unhash_openowner_locked\n                          list_del_init(\u0026oo-\u003eoo_perclient)\n                          // cannot find this oo\n                          // from client, LEAK!!!\n                         alloc_stateowner // alloc oo2\n\n nfsd4_process_open2\n  init_open_stateid\n  // associate oo1\n  // with stateid1, stateid1 LEAK!!!\n  nfs4_get_vfs_file\n  // alloc nfsd_file1 and nfsd_file_mark1\n  // all LEAK!!!\n\n                         nfsd4_process_open2\n                         ...\n\n                                    write_threads\n                                     ...\n                                     nfsd_destroy_serv\n                                      nfsd_shutdown_net\n                                       nfs4_state_shutdown_net\n                                        nfs4_state_destroy_net\n                                         destroy_client\n                                          __destroy_client\n                                          // won\u0027t find oo1!!!\n                                     nfsd_shutdown_generic\n                                      nfsd_file_cache_shutdown\n                                       kmem_cache_destroy\n                                       for nfsd_file_slab\n                                       and nfsd_file_mark_slab\n                                       // bark since nfsd_file1\n                                       // and nfsd_file_mark1\n                                       // still alive\n\n=======================================================================\nBUG nfsd_file (Not tainted): Objects remaining in nfsd_file on\n__kmem_cache_shutdown()\n-----------------------------------------------------------------------\n\nSlab 0xffd4000004438a80 objects=34 used=1 fp=0xff11000110e2ad28\nflags=0x17ffffc0000240(workingset|head|node=0|zone=2|lastcpupid=0x1fffff)\nCPU: 4 UID: 0 PID: 757 Comm: sh Not tainted 6.12.0-rc6+ #19\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS\n1.16.1-2.fc37 04/01/2014\nCall Trace:\n \u003cTASK\u003e\n dum\n---truncated---"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The vulnerable code is nfsd\u0027s NFSv4 OPEN handler, reached from `svc_process()` \u2192 `nfsd_dispatch()` \u2192 `nfsd4_proc_compound()` \u2192 `nfsd4_open()` on data received from a remote NFS client over routable TCP port 2049. No local access or network adjacency is required.\nAC:L - The attacker owns both sides of the race \u2014 it simply opens two TCP connections under one clientid and issues two concurrent NFSv4.0 COMPOUND OPENs carrying the same fresh (unconfirmed) open_owner, and the default 8 nfsd threads guarantee parallel service. The window spans all of `nfsd4_process_open2()` including the VFS open and disk I/O, and a failed attempt costs nothing and can be retried indefinitely.\nPR:N - NFS with the default AUTH_SYS flavour performs no authentication whatsoever \u2014 the client self-asserts its uid \u2014 so any host permitted by the export list (routinely a whole subnet or `*`) can issue SETCLIENTID, PUTROOTFH/LOOKUP and OPEN with no credentials verified. Nothing on the path to `find_or_alloc_open_stateowner()` checks any capability or privilege.\nUI:N - The attacker\u0027s own client issues both concurrent OPEN requests and the later conflicting OPEN entirely on its own initiative; no action by a local user or administrator is needed to trigger the leak or reach the stale stateid.\nS:U - The leaked objects, the dangling `nfs4_client` pointer and any resulting panic all remain inside the kernel\u0027s own security authority on the NFS server host. No VM, IOMMU or sandbox boundary is crossed.\nC:H - The leak breaks the invariant that all stateids are destroyed before `free_client()`, leaving `stp-\u003est_stid.sc_client` dangling after routine lease expiry while `stp` keeps `fp` hashed in the global `nfs4_file_rhltable`; a later OPEN with a conflicting share mode reads that freed `nfs4_client` in `nfs4_resolve_deny_conflicts_locked()`. Unauthenticated SETCLIENTID lets the attacker spray `client_slab` to control and observe the reclaimed object, and per kernel guidance a use-after-free is scored High.\nI:H - `try_to_expire_client()` performs a `cmpxchg()` on `clp-\u003ecl_state` of the freed, attacker-groomable `nfs4_client`, giving a write primitive into reclaimed heap memory. Additionally the leaked `nfsd_file_mark` survives `nfsd_file_cache_shutdown()` as a live fsnotify mark whose group ops point into nfsd module text, corrupting control flow if the module is later unloaded.\nA:H - Each won race permanently leaks an openowner, stateid, `nfs4_file`, `nfsd_file`, `nfsd_file_mark` and an open `struct file` that pins the inode, dentry and mount, so a remote client looping the race exhausts kernel memory and file references and makes the exported filesystem unmountable. On top of that, `kmem_cache_destroy()` fires `WARN(err, \"Slab cache still has objects\u2026\")` at nfsd shutdown \u2014 an immediate panic under `panic_on_warn=1` \u2014 and the use-after-free itself crashes the server."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T11:46:27.780Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/a85364f0d30dee01c5d5b4afa55a9629a8f36d8e"
        },
        {
          "url": "https://git.kernel.org/stable/c/2d505a801e57428057563762f67a5a62009b2600"
        },
        {
          "url": "https://git.kernel.org/stable/c/0ab0a3ad24e970e894abcac58f85c332d1726749"
        },
        {
          "url": "https://git.kernel.org/stable/c/45abb68c941ebc9a35c6d3a7b08196712093c636"
        },
        {
          "url": "https://git.kernel.org/stable/c/37dfc81266d3a32294524bfadd3396614f8633ee"
        },
        {
          "url": "https://git.kernel.org/stable/c/6f73f920b7ad0084373e46121d7ac34117aed652"
        },
        {
          "url": "https://git.kernel.org/stable/c/98100e88dd8865999dc6379a3356cd799795fe7b"
        }
      ],
      "title": "nfsd: fix nfs4_openowner leak when concurrent nfsd4_open occur",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2024-56779",
    "datePublished": "2025-01-08T17:49:17.070Z",
    "dateReserved": "2024-12-29T11:26:39.767Z",
    "dateUpdated": "2026-08-05T11:46:27.780Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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EUVD-2026-346537

CVE-2024-56779 (GCVE-0-2024-56779)

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Sightings

Nomenclature

Related by attack behaviour