Vulnerability-Lookup

GHSA-5PHX-C495-RGX5

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-11 21:31

Details

In the Linux kernel, the following vulnerability has been resolved:

dm-pcache: validate on-media seg_num against the cache device size

seg_num is read from the crc32c-only superblock, so whoever supplies the cache device on a table load (CAP_SYS_ADMIN) controls it. It sizes cache->segments[] and is the value every later on-media segment id is bounded against, yet it is never checked against the device. Because cache_dev->mapping is the direct map of the pmem, CACHE_DEV_SEGMENT() for a segment id past the device resolves to ordinary kernel memory beyond the mapping; a new-cache init reaching such an id has cache_seg_init() -> cache_dev_zero_range() memset() 12 KiB over that memory -- an out-of-bounds write into the kernel heap at table load. A zero seg_num makes the segment allocations ZERO_SIZE_PTR.

Reject a seg_num that is zero, larger than the device can hold, or larger than PCACHE_CACHE_SEGS_MAX before it is used.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-80960"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:19:01Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm-pcache: validate on-media seg_num against the cache device size\n\nseg_num is read from the crc32c-only superblock, so whoever supplies the\ncache device on a table load (CAP_SYS_ADMIN) controls it. It sizes\ncache-\u003esegments[] and is the value every later on-media segment id is\nbounded against, yet it is never checked against the device. Because\ncache_dev-\u003emapping is the direct map of the pmem, CACHE_DEV_SEGMENT() for\na segment id past the device resolves to ordinary kernel memory beyond\nthe mapping; a new-cache init reaching such an id has cache_seg_init() -\u003e\ncache_dev_zero_range() memset() 12 KiB over that memory -- an\nout-of-bounds write into the kernel heap at table load. A zero seg_num\nmakes the segment allocations ZERO_SIZE_PTR.\n\nReject a seg_num that is zero, larger than the device can hold, or larger\nthan PCACHE_CACHE_SEGS_MAX before it is used.",
  "id": "GHSA-5phx-c495-rgx5",
  "modified": "2026-09-11T21:31:21Z",
  "published": "2026-09-11T21:31:21Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80960"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/62d92e45abe9e087370f9fc5d876b95673aced34"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/91b93fe5cf4d62d5ecc642a6c8f15a3c11b00e3c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e889c0ee81165fc90aad2979b51f930f77895703"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-80960 (GCVE-0-2026-80960)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:42 – Updated: 2026-09-11 19:42

Title

dm-pcache: validate on-media seg_num against the cache device size

Summary

In the Linux kernel, the following vulnerability has been resolved: dm-pcache: validate on-media seg_num against the cache device size seg_num is read from the crc32c-only superblock, so whoever supplies the cache device on a table load (CAP_SYS_ADMIN) controls it. It sizes cache->segments[] and is the value every later on-media segment id is bounded against, yet it is never checked against the device. Because cache_dev->mapping is the direct map of the pmem, CACHE_DEV_SEGMENT() for a segment id past the device resolves to ordinary kernel memory beyond the mapping; a new-cache init reaching such an id has cache_seg_init() -> cache_dev_zero_range() memset() 12 KiB over that memory -- an out-of-bounds write into the kernel heap at table load. A zero seg_num makes the segment allocations ZERO_SIZE_PTR. Reject a seg_num that is zero, larger than the device can hold, or larger than PCACHE_CACHE_SEGS_MAX before it is used.

Severity

No CVSS data available.

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/91b93fe5cf4d62d5e…
https://git.kernel.org/stable/c/e889c0ee81165fc90…
https://git.kernel.org/stable/c/62d92e45abe9e0873…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 , < 91b93fe5cf4d62d5ecc642a6c8f15a3c11b00e3c (git) Affected: 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 , < e889c0ee81165fc90aad2979b51f930f77895703 (git) Affected: 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 , < 62d92e45abe9e087370f9fc5d876b95673aced34 (git)
Linux	Linux	Affected: 6.18 Unaffected: 0 , < 6.18 (semver) Unaffected: 6.18.50 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/md/dm-pcache/cache_dev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "91b93fe5cf4d62d5ecc642a6c8f15a3c11b00e3c",
              "status": "affected",
              "version": "1d57628ff95b32d5cfa8d8f50e07690c161e9cf0",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "1d57628ff95b32d5cfa8d8f50e07690c161e9cf0",
              "versionType": "git"
            },
            {
              "lessThan": "62d92e45abe9e087370f9fc5d876b95673aced34",
              "status": "affected",
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              "versionType": "git"
            }
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          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
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            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
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          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                }
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              "negate": false,
              "operator": "OR"
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        }
      ],
      "descriptions": [
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm-pcache: validate on-media seg_num against the cache device size\n\nseg_num is read from the crc32c-only superblock, so whoever supplies the\ncache device on a table load (CAP_SYS_ADMIN) controls it. It sizes\ncache-\u003esegments[] and is the value every later on-media segment id is\nbounded against, yet it is never checked against the device. Because\ncache_dev-\u003emapping is the direct map of the pmem, CACHE_DEV_SEGMENT() for\na segment id past the device resolves to ordinary kernel memory beyond\nthe mapping; a new-cache init reaching such an id has cache_seg_init() -\u003e\ncache_dev_zero_range() memset() 12 KiB over that memory -- an\nout-of-bounds write into the kernel heap at table load. A zero seg_num\nmakes the segment allocations ZERO_SIZE_PTR.\n\nReject a seg_num that is zero, larger than the device can hold, or larger\nthan PCACHE_CACHE_SEGS_MAX before it is used."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-11T19:42:27.182Z",
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        {
          "url": "https://git.kernel.org/stable/c/62d92e45abe9e087370f9fc5d876b95673aced34"
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      ],
      "title": "dm-pcache: validate on-media seg_num against the cache device size",
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        "engine": "bippy-1.2.0"
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    "datePublished": "2026-09-11T19:42:27.182Z",
    "dateReserved": "2026-08-26T14:34:25.809Z",
    "dateUpdated": "2026-09-11T19:42:27.182Z",
    "state": "PUBLISHED"
  },
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}

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.

Detection rules are retrieved from Rulezet.

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