Vulnerability-Lookup

EUVD-2026-372832

European Vulnerability Database identifier assigned by ENISA

Reserved

2026-10-02 08:39

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.

JSON

To clipboard

{
  "assigner": "ENISA",
  "date_reserved": "2026-10-02T08:39:23.165207+00:00",
  "id": "EUVD-2026-372832"
}

CVE-2026-89544 (GCVE-0-2026-89544)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:44 – Updated: 2026-09-21 13:14

Title

SUNRPC: fix gssx_dec_option_array error path bugs

Summary

In the Linux kernel, the following vulnerability has been resolved: SUNRPC: fix gssx_dec_option_array error path bugs Four coupled defects in the gssx XDR option-array decoder make the error paths unsafe: a NULL deref in the caller, a refcount leak on the decoded group_info, and a latent use-after-free that the leak fix would otherwise expose. gssx_dec_option_array() sets oa->count = 1 before allocating oa->data. If that allocation fails, -ENOMEM is returned with oa->count == 1 and oa->data == NULL. All other error paths jump to free_oa: which frees oa->data and NULLs it but also leaves oa->count == 1. The caller trusts the count: gssp_accept_sec_context_upcall() gssx_dec_accept_sec_context() gssx_dec_option_array() /* fails, count=1 data=NULL */ data = res.options.data[0].value /* NULL deref */ Independently, free_creds: releases the partially decoded svc_cred with a bare kfree(creds). gssx_dec_linux_creds() installs a groups_alloc() result into creds->cr_group_info; that object is kvmalloc-backed and refcounted, and only put_group_info() reaches kvfree(). A plain kfree(creds) drops the wrapper and leaks the group_info allocation. The natural fix for the leak is to call free_svc_cred(creds) before kfree(creds), but free_svc_cred() invokes put_group_info() on creds->cr_group_info unconditionally when non-NULL. The existing out_free_groups: path in gssx_dec_linux_creds() already called groups_free() on that pointer without clearing it, so once free_svc_cred() is wired in, the subsequent put_group_info() would touch freed memory. Fix all four together: - Move the oa->count = 1 assignment below the oa->data allocation so it is never set when oa->data is NULL. - Reset oa->count to 0 at free_oa: so count and data stay coherent and the caller sees an empty option array. - Call free_svc_cred(creds) before kfree(creds) at free_creds: so the refcounted cr_group_info is released. free_svc_cred() either NULL-guards each field explicitly (cr_group_info has an if() check) or delegates to a helper that is NULL-safe itself (kfree for the string fields, gss_mech_put() which guards with if(gm) at gss_mech_switch.c:342), so it is safe to call on a partially decoded svc_cred where only cr_uid/cr_gid/cr_group_info have been written and everything else is zero from kzalloc. - In gssx_dec_linux_creds()'s out_free_groups: path, release cr_group_info with put_group_info() rather than groups_free() so the teardown matches free_svc_cred()'s refcount-aware path, and clear the pointer so a later free_svc_cred() on the same creds does not release it a second time.

Severity

7.5 (High)


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

Assigner

Linux mitre root Scorecard

References

4 references

URL	Tags
https://git.kernel.org/stable/c/fb30241f7ccace372…
https://git.kernel.org/stable/c/3ff45361e9469e85c…
https://git.kernel.org/stable/c/f85a83774d7f4e2ac…
https://git.kernel.org/stable/c/5e9a94539b1ec17a8…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 3cfcfc102a5e57b021b786a755a38935e357797d , < fb30241f7ccace372ee83017891549f23a715581 (git) Affected: 3cfcfc102a5e57b021b786a755a38935e357797d , < 3ff45361e9469e85c0f86b8e7b82c63e50bab8ef (git) Affected: 3cfcfc102a5e57b021b786a755a38935e357797d , < f85a83774d7f4e2ac71c0c384df0dfb6f7d0179a (git) Affected: 3cfcfc102a5e57b021b786a755a38935e357797d , < 5e9a94539b1ec17a89177d952badfd0d844d694a (git) Affected: b97c37978ca825557d331c9012e0c1ddc0e42364 (git) Affected: bfa9d86d39a0fe4685f90c3529aa9bd62a9d97a8 (git) Affected: bb336cd8d5ecb69c430ebe3e7bcff68471d93fa8 (git) Affected: dd292e884c649f9b1c18af0ec75ca90b390cd044 (git) Affected: 934212a623cbab851848b6de377eb476718c3e4c (git) Affected: 5e6013ae2c8d420faea553d363935f65badd32c3 (git) Affected: 9806c2393cd2ab0a8e7bb9ffae02ce20e3112ec4 (git) Affected: 996997d1fb2126feda550d6adcedcbd94911fc69 (git) Affected: 4.19.311 , < 4.20 (semver) Affected: 5.4.273 , < 5.5 (semver) Affected: 5.10.214 , < 5.11 (semver) Affected: 5.15.153 , < 5.16 (semver) Affected: 6.1.83 , < 6.2 (semver) Affected: 6.6.23 , < 6.7 (semver) Affected: 6.7.11 , < 6.8 (semver) Affected: 6.8.2 , < 6.9 (semver)
Linux	Linux	Affected: 6.9 Unaffected: 0 , < 6.9 (semver) Unaffected: 6.12.111 , ≤ 6.12.* (semver) Unaffected: 6.18.51 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sunrpc/auth_gss/gss_rpc_xdr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "fb30241f7ccace372ee83017891549f23a715581",
              "status": "affected",
              "version": "3cfcfc102a5e57b021b786a755a38935e357797d",
              "versionType": "git"
            },
            {
              "lessThan": "3ff45361e9469e85c0f86b8e7b82c63e50bab8ef",
              "status": "affected",
              "version": "3cfcfc102a5e57b021b786a755a38935e357797d",
              "versionType": "git"
            },
            {
              "lessThan": "f85a83774d7f4e2ac71c0c384df0dfb6f7d0179a",
              "status": "affected",
              "version": "3cfcfc102a5e57b021b786a755a38935e357797d",
              "versionType": "git"
            },
            {
              "lessThan": "5e9a94539b1ec17a89177d952badfd0d844d694a",
              "status": "affected",
              "version": "3cfcfc102a5e57b021b786a755a38935e357797d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b97c37978ca825557d331c9012e0c1ddc0e42364",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "bfa9d86d39a0fe4685f90c3529aa9bd62a9d97a8",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "bb336cd8d5ecb69c430ebe3e7bcff68471d93fa8",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "dd292e884c649f9b1c18af0ec75ca90b390cd044",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "934212a623cbab851848b6de377eb476718c3e4c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5e6013ae2c8d420faea553d363935f65badd32c3",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9806c2393cd2ab0a8e7bb9ffae02ce20e3112ec4",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "996997d1fb2126feda550d6adcedcbd94911fc69",
              "versionType": "git"
            },
            {
              "lessThan": "4.20",
              "status": "affected",
              "version": "4.19.311",
              "versionType": "semver"
            },
            {
              "lessThan": "5.5",
              "status": "affected",
              "version": "5.4.273",
              "versionType": "semver"
            },
            {
              "lessThan": "5.11",
              "status": "affected",
              "version": "5.10.214",
              "versionType": "semver"
            },
            {
              "lessThan": "5.16",
              "status": "affected",
              "version": "5.15.153",
              "versionType": "semver"
            },
            {
              "lessThan": "6.2",
              "status": "affected",
              "version": "6.1.83",
              "versionType": "semver"
            },
            {
              "lessThan": "6.7",
              "status": "affected",
              "version": "6.6.23",
              "versionType": "semver"
            },
            {
              "lessThan": "6.8",
              "status": "affected",
              "version": "6.7.11",
              "versionType": "semver"
            },
            {
              "lessThan": "6.9",
              "status": "affected",
              "version": "6.8.2",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/sunrpc/auth_gss/gss_rpc_xdr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.9"
            },
            {
              "lessThan": "6.9",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.51",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.19.311",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.4.273",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.10.214",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.15.153",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.1.83",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.6.23",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.7.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.8.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: fix gssx_dec_option_array error path bugs\n\nFour coupled defects in the gssx XDR option-array decoder make the\nerror paths unsafe: a NULL deref in the caller, a refcount leak on\nthe decoded group_info, and a latent use-after-free that the leak\nfix would otherwise expose.\n\ngssx_dec_option_array() sets oa-\u003ecount = 1 before allocating\noa-\u003edata.  If that allocation fails, -ENOMEM is returned with\noa-\u003ecount == 1 and oa-\u003edata == NULL.  All other error paths jump\nto free_oa: which frees oa-\u003edata and NULLs it but also leaves\noa-\u003ecount == 1.  The caller trusts the count:\n\n    gssp_accept_sec_context_upcall()\n      gssx_dec_accept_sec_context()\n        gssx_dec_option_array()        /* fails, count=1 data=NULL */\n      data = res.options.data[0].value /* NULL deref */\n\nIndependently, free_creds: releases the partially decoded svc_cred\nwith a bare kfree(creds).  gssx_dec_linux_creds() installs a\ngroups_alloc() result into creds-\u003ecr_group_info; that object is\nkvmalloc-backed and refcounted, and only put_group_info() reaches\nkvfree().  A plain kfree(creds) drops the wrapper and leaks the\ngroup_info allocation.\n\nThe natural fix for the leak is to call free_svc_cred(creds) before\nkfree(creds), but free_svc_cred() invokes put_group_info() on\ncreds-\u003ecr_group_info unconditionally when non-NULL.  The existing\nout_free_groups: path in gssx_dec_linux_creds() already called\ngroups_free() on that pointer without clearing it, so once\nfree_svc_cred() is wired in, the subsequent put_group_info() would\ntouch freed memory.\n\nFix all four together:\n\n  - Move the oa-\u003ecount = 1 assignment below the oa-\u003edata allocation\n    so it is never set when oa-\u003edata is NULL.\n  - Reset oa-\u003ecount to 0 at free_oa: so count and data stay\n    coherent and the caller sees an empty option array.\n  - Call free_svc_cred(creds) before kfree(creds) at free_creds:\n    so the refcounted cr_group_info is released.  free_svc_cred()\n    either NULL-guards each field explicitly (cr_group_info has\n    an if() check) or delegates to a helper that is NULL-safe\n    itself (kfree for the string fields, gss_mech_put() which\n    guards with if(gm) at gss_mech_switch.c:342), so it is safe\n    to call on a partially decoded svc_cred where only\n    cr_uid/cr_gid/cr_group_info have been written and everything\n    else is zero from kzalloc.\n  - In gssx_dec_linux_creds()\u0027s out_free_groups: path, release\n    cr_group_info with put_group_info() rather than groups_free()\n    so the teardown matches free_svc_cred()\u0027s refcount-aware path,\n    and clear the pointer so a later free_svc_cred() on the same\n    creds does not release it a second time."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The decoder runs only as a consequence of an RPCSEC_GSS_INIT/CONTINUE_INIT Call to in-kernel nfsd (and other SUNRPC servers such as lockd) on the network, typically TCP/2049. A remote client drives svcauth_gss_proxy_init() \u2192 gssp_accept_sec_context_upcall() \u2192 gssx_dec_option_array(); the attacker\u2019s reach is purely over the network.\nAC:L - Any allocation or XDR error after oa-\u003ecount is set to 1 leaves count=1 with data=NULL, and the caller always indexes res.options.data[0]. The attacker can induce those failures by flooding pre-auth GSS_INIT upcalls that each pin 256 KB of receive pages (especially under memcg-limited nfsd) and by driving large group-list replies, so success does not depend on conditions beyond their control.\nPR:N - svcauth_gss_proxy_init() runs from svcauth_gss_proc_init() on the first RPCSEC_GSS handshake leg, before the kernel has validated any Kerberos ticket. The upcall and option-array decode execute for an unauthenticated NFS client; no local account or prior credential on the server is required.\nUI:N - The crash is triggered entirely by an inbound RPC to an already-running nfsd/SUNRPC service thread. No administrator or end-user action such as mounting a filesystem or opening a file is required.\nS:U - The NULL dereference and group_info leak occur inside the host kernel\u2019s SUNRPC/GSS code. Impact stays within that kernel\u2019s security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:N - With oa-\u003ecount==1 and oa-\u003edata==NULL, gssp_accept_sec_context_upcall() does \u0026res.options.data[0].value, a NULL+small-offset load that faults on the unmapped zero page. No kernel memory is returned to the attacker; unlike a UAF, freed object contents are never read.\nI:N - The faulting access is a pure NULL-pointer dereference with no kernel write. The put_group_info() UAF described in the fix is only latent: the unpatched free_creds path kfree()s the svc_cred wrapper without touching cr_group_info, so the dangling pointer is not used.\nA:H - The NULL dereference oopses the nfsd (or lockd) thread and panics the host where panic_on_oops is set, which is typical on NAS/appliance NFS servers. The same error path also leaks the kvmalloc-backed group_info, and the crash can be repeated to take down SUNRPC service threads."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-21T13:14:24.848Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/fb30241f7ccace372ee83017891549f23a715581"
        },
        {
          "url": "https://git.kernel.org/stable/c/3ff45361e9469e85c0f86b8e7b82c63e50bab8ef"
        },
        {
          "url": "https://git.kernel.org/stable/c/f85a83774d7f4e2ac71c0c384df0dfb6f7d0179a"
        },
        {
          "url": "https://git.kernel.org/stable/c/5e9a94539b1ec17a89177d952badfd0d844d694a"
        }
      ],
      "title": "SUNRPC: fix gssx_dec_option_array error path bugs",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89544",
    "datePublished": "2026-09-11T19:44:20.424Z",
    "dateReserved": "2026-09-11T19:38:34.722Z",
    "dateUpdated": "2026-09-21T13:14:24.848Z",
    "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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

EUVD-2026-372832

CVE-2026-89544 (GCVE-0-2026-89544)

Tags

Sightings

Nomenclature

Related by attack behaviour