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EUVD-2026-376126

European Vulnerability Database identifier assigned by ENISA

Reserved

2026-10-02 08:40

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": "2026-10-02T08:40:05.971340+00:00",
  "id": "EUVD-2026-376126"
}

CVE-2026-98116 (GCVE-0-2026-98116)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:36 – Updated: 2026-10-03 11:02

Title

ALSA: pcm: Serialize PCM mmap with buffer reallocation to fix page UAF

Summary

In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: Serialize PCM mmap with buffer reallocation to fix page UAF snd_pcm_hw_params() and snd_pcm_hw_free() guard buffer reallocation with an mmap_count check performed under the PCM stream lock, but the lock is released long before the buffer is actually freed: snd_pcm_sync_stop(), constraint refinement and do_free_pages() all happen in between. snd_pcm_mmap_data(), on the other hand, takes no lock at all: it validates against the old buffer's state and dma_bytes, remaps its pages into the VMA, and only then increments mmap_count. A concurrent mmap() can therefore slip in between the check and the free. remap_pfn_range() installs writable PTEs for the old buffer's pages without taking page references, and the subsequent do_free_pages() returns those pages to the page allocator while the VMA still maps them. This leaves a stale, writable mapping of freed pages: a page-level use-after-free that can be leveraged for local privilege escalation. Make snd_pcm_mmap_data() participate in the buffer-access scheme introduced for hw_params/hw_free: acquire runtime->buffer_accessing before validating and remapping, and release it afterwards. Buffer reallocation already fails with -EBUSY while accessors are active, and the mmap side now fails with -EBUSY while a reallocation is in progress, so the validate/remap sequence and the check/free sequence can no longer interleave. A reproducer that turns this race into a stale writable mapping of the freed DMA buffer pages is available on request.

Severity

7.8 (High)


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

Assigner

Linux mitre root Scorecard

References

7 references

URL	Tags
https://git.kernel.org/stable/c/e6cdd2a0470d64073…
https://git.kernel.org/stable/c/9857a75714bb5df47…
https://git.kernel.org/stable/c/cbadf2575d25e7dcc…
https://git.kernel.org/stable/c/cbc7ec97601d09b74…
https://git.kernel.org/stable/c/fd137bf8149bc6460…
https://git.kernel.org/stable/c/8c1882dfee8f404d1…
https://git.kernel.org/stable/c/9b110a9dcecc59516…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 33061d0fba51d2bf70a2ef9645f703c33fe8e438 , < e6cdd2a0470d64073349a970dc1691433804b271 (git) Affected: 92ee3c60ec9fe64404dc035e7c41277d74aa26cb , < 9857a75714bb5df4781e4d8b1a1753b1e17bf07a (git) Affected: 92ee3c60ec9fe64404dc035e7c41277d74aa26cb , < cbadf2575d25e7dcc0d4da2717817ae569fbc99b (git) Affected: 92ee3c60ec9fe64404dc035e7c41277d74aa26cb , < cbc7ec97601d09b74e05e44470fa6b0bcdabf3f5 (git) Affected: 92ee3c60ec9fe64404dc035e7c41277d74aa26cb , < fd137bf8149bc6460f9b7b1fc292025da04cb9ee (git) Affected: 92ee3c60ec9fe64404dc035e7c41277d74aa26cb , < 8c1882dfee8f404d118020664b73eb4592172226 (git) Affected: 92ee3c60ec9fe64404dc035e7c41277d74aa26cb , < 9b110a9dcecc59516c77cb3c0caf1f492f75df2d (git) Affected: a42aa926843acca96c0dfbde2e835b8137f2f092 (git) Affected: 9cb6c40a6ebe4a0cfc9d6a181958211682cffea9 (git) Affected: fbeb492694ce0441053de57699e1e2b7bc148a69 (git) Affected: 0f6947f5f5208f6ebd4d76a82a4757e2839a23f8 (git) Affected: 0090c13cbbdffd7da079ac56f80373a9a1be0bf8 (git) Affected: 1bbf82d9f961414d6c76a08f7f843ea068e0ab7b (git) Affected: 5.15.32 , < 5.15.222 (semver) Affected: 4.14.279 , < 4.15 (semver) Affected: 4.19.243 , < 4.20 (semver) Affected: 5.4.193 , < 5.5 (semver) Affected: 5.10.109 , < 5.11 (semver) Affected: 5.16.18 , < 5.17 (semver) Affected: 5.17.1 , < 5.18 (semver)
Linux	Linux	Affected: 5.18 Unaffected: 0 , < 5.18 (semver) Unaffected: 5.15.222 , ≤ 5.15.* (semver) Unaffected: 6.1.189 , ≤ 6.1.* (semver) Unaffected: 6.6.158 , ≤ 6.6.* (semver) Unaffected: 6.12.111 , ≤ 6.12.* (semver) Unaffected: 6.18.53 , ≤ 6.18.* (semver) Unaffected: 7.2.7 , ≤ 7.2.* (semver) Unaffected: 7.3-rc2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "sound/core/pcm_native.c"
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          "vendor": "Linux",
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              "versionType": "git"
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              "versionType": "git"
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              "versionType": "git"
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              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "0090c13cbbdffd7da079ac56f80373a9a1be0bf8",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1bbf82d9f961414d6c76a08f7f843ea068e0ab7b",
              "versionType": "git"
            },
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              "status": "affected",
              "version": "5.15.32",
              "versionType": "semver"
            },
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              "status": "affected",
              "version": "4.14.279",
              "versionType": "semver"
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              "status": "affected",
              "version": "4.19.243",
              "versionType": "semver"
            },
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              "versionType": "semver"
            },
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              "lessThan": "5.17",
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              "version": "5.16.18",
              "versionType": "semver"
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              "status": "affected",
              "version": "5.17.1",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "sound/core/pcm_native.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.18"
            },
            {
              "lessThan": "5.18",
              "status": "unaffected",
              "version": "0",
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            },
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              "status": "unaffected",
              "version": "5.15.222",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.189",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.222",
                  "versionStartIncluding": "5.15.32",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.189",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
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                  "vulnerable": true
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                  "versionEndExcluding": "6.12.111",
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                  "vulnerable": true
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                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.7",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc2",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.14.279",
                  "vulnerable": true
                },
                {
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                },
                {
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              "negate": false,
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: pcm: Serialize PCM mmap with buffer reallocation to fix page UAF\n\nsnd_pcm_hw_params() and snd_pcm_hw_free() guard buffer reallocation\nwith an mmap_count check performed under the PCM stream lock, but the\nlock is released long before the buffer is actually freed:\nsnd_pcm_sync_stop(), constraint refinement and do_free_pages() all\nhappen in between.  snd_pcm_mmap_data(), on the other hand, takes no\nlock at all: it validates against the old buffer\u0027s state and\ndma_bytes, remaps its pages into the VMA, and only then increments\nmmap_count.\n\nA concurrent mmap() can therefore slip in between the check and the\nfree.  remap_pfn_range() installs writable PTEs for the old buffer\u0027s\npages without taking page references, and the subsequent\ndo_free_pages() returns those pages to the page allocator while the\nVMA still maps them.  This leaves a stale, writable mapping of freed\npages: a page-level use-after-free that can be leveraged for local\nprivilege escalation.\n\nMake snd_pcm_mmap_data() participate in the buffer-access scheme\nintroduced for hw_params/hw_free: acquire runtime-\u003ebuffer_accessing\nbefore validating and remapping, and release it afterwards.  Buffer\nreallocation already fails with -EBUSY while accessors are active,\nand the mmap side now fails with -EBUSY while a reallocation is in\nprogress, so the validate/remap sequence and the check/free sequence\ncan no longer interleave.\n\nA reproducer that turns this race into a stale writable mapping of\nthe freed DMA buffer pages is available on request."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is triggered by mmap() on a local /dev/snd/pcmC*D* file descriptor (snd_pcm_mmap -\u003e snd_pcm_mmap_data) racing with SNDRV_PCM_IOCTL_HW_PARAMS/HW_FREE ioctls on the same fd. No remote protocol carries any of the inputs.\nAC:L - One process controls both sides of the race: one thread calls mmap() and another calls hw_free/hw_params. The window runs from the mmap_count check under the stream lock through snd_pcm_sync_stop and refinement to do_free_pages, and the attacker can retry as often as needed.\nPR:L - Opening the PCM device node takes ordinary local user access, either the audio group or the udev uaccess ACL given to the logged-in seat user. No capability is checked on the mmap or hw_params/hw_free paths.\nUI:N - The attacker opens the device, sets hw_params and races the mmap against hw_free entirely through their own syscalls. No other user has to do anything.\nS:U - This is a local kernel privilege escalation within the same kernel security authority. It crosses no VM or IOMMU boundary.\nC:H - remap_pfn_range installs PTEs for the old DMA buffer pages without taking page references, and do_free_pages then frees them. The attacker keeps a direct mapping of whatever the page allocator reuses those pages for, such as page tables, cred or slab pages, and can read it.\nI:H - The stale mapping of the freed buffer pages is writable, which gives direct write access to reallocated kernel pages. This is a page-level UAF that enables privilege escalation, as the fix commit itself states.\nA:H - Writing through the stale PTEs into pages that have been reallocated corrupts arbitrary kernel memory, which leads to oopses, panics or page-state BUGs."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-03T11:02:31.328Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e6cdd2a0470d64073349a970dc1691433804b271"
        },
        {
          "url": "https://git.kernel.org/stable/c/9857a75714bb5df4781e4d8b1a1753b1e17bf07a"
        },
        {
          "url": "https://git.kernel.org/stable/c/cbadf2575d25e7dcc0d4da2717817ae569fbc99b"
        },
        {
          "url": "https://git.kernel.org/stable/c/cbc7ec97601d09b74e05e44470fa6b0bcdabf3f5"
        },
        {
          "url": "https://git.kernel.org/stable/c/fd137bf8149bc6460f9b7b1fc292025da04cb9ee"
        },
        {
          "url": "https://git.kernel.org/stable/c/8c1882dfee8f404d118020664b73eb4592172226"
        },
        {
          "url": "https://git.kernel.org/stable/c/9b110a9dcecc59516c77cb3c0caf1f492f75df2d"
        }
      ],
      "title": "ALSA: pcm: Serialize PCM mmap with buffer reallocation to fix page UAF",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98116",
    "datePublished": "2026-09-25T10:36:01.723Z",
    "dateReserved": "2026-09-25T10:25:14.317Z",
    "dateUpdated": "2026-10-03T11:02:31.328Z",
    "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.

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EUVD-2026-376126

CVE-2026-98116 (GCVE-0-2026-98116)

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