CVE-2026-80962 (GCVE-0-2026-80962)
Vulnerability from cvelistv5
Published
2026-09-11 19:42
Modified
2026-10-19 08:45
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: dm-pcache: validate geometry fields from on-disk cache_info cache_segs_init() iterates cache_info->n_segs times indexing cache->segments[], which is sized to the cache device geometry, and get_seg_id() takes each segment id from the on-media cache_info and the per-segment next_seg link. Both come from cache device metadata that is only CRC-protected with a fixed public seed, so whoever supplies the cache device on a table load (CAP_SYS_ADMIN) controls them: an oversized n_segs or an out-of-range id drives an out-of-bounds access of cache->segments[] and a wild CACHE_DEV_SEGMENT() pointer into the device mapping -- an out-of-bounds read and write from on-disk data. Reject an n_segs that exceeds the device segment count and a segment id that is out of range before either is used. Valid metadata is unaffected.
References
Impacted products
Vendor Product Version
Linux Linux Version: 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0
Version: 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0
Version: 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/md/dm-pcache/cache.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ab5dcde6fa96bc115b85f3621c60e39c66229a90",
              "status": "affected",
              "version": "1d57628ff95b32d5cfa8d8f50e07690c161e9cf0",
              "versionType": "git"
            },
            {
              "lessThan": "3e19172089ec81132a8a48e802b1034a744209f4",
              "status": "affected",
              "version": "1d57628ff95b32d5cfa8d8f50e07690c161e9cf0",
              "versionType": "git"
            },
            {
              "lessThan": "32d1809da31094ef76fd98dc1f1a8b55ca1295dd",
              "status": "affected",
              "version": "1d57628ff95b32d5cfa8d8f50e07690c161e9cf0",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/md/dm-pcache/cache.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm-pcache: validate geometry fields from on-disk cache_info\n\ncache_segs_init() iterates cache_info-\u003en_segs times indexing\ncache-\u003esegments[], which is sized to the cache device geometry, and\nget_seg_id() takes each segment id from the on-media cache_info and the\nper-segment next_seg link. Both come from cache device metadata that is\nonly CRC-protected with a fixed public seed, so whoever supplies the\ncache device on a table load (CAP_SYS_ADMIN) controls them: an oversized\nn_segs or an out-of-range id drives an out-of-bounds access of\ncache-\u003esegments[] and a wild CACHE_DEV_SEGMENT() pointer into the device\nmapping -- an out-of-bounds read and write from on-disk data.\n\nReject an n_segs that exceeds the device segment count and a segment id\nthat is out of range before either is used. Valid metadata is unaffected."
        }
      ],
      "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 OOB access is reached only through a local device-mapper table load on /dev/mapper/control (ctl_ioctl \u2192 table_load \u2192 populate_table \u2192 dm_pcache_ctr \u2192 pcache_start \u2192 pcache_cache_start \u2192 cache_segs_init/get_seg_id). No network, Bluetooth, or USB path feeds on-disk cache_info geometry.\nAC:L - The attacker fully controls on-media cache_info.n_segs, cache_info.seg_id and each segment next_seg, and can forge a passing CRC because PCACHE_CRC_SEED (0x3B15A) is public, so a crafted INIT_DONE image with oversized n_segs or out-of-range ids hits the OOB on every table load with no race.\nPR:L - ctl_ioctl gates DM_TABLE_LOAD with capable(CAP_SYS_ADMIN). In the most severe reasonable deployment that capability is held by a container or storage-stack administrator with delegated mapper and DAX/pmem nodes rather than exclusive host root, which kernel-CNA scoring of device-mapper table-load bugs maps to Low.\nUI:N - The attacker crafts the DAX cache-device metadata and issues DM_TABLE_LOAD themselves; no separate victim must mount a filesystem, open a file, or otherwise interact.\nS:U - Out-of-bounds indexing of cache-\u003esegments[] and wild CACHE_DEV_SEGMENT() pointers corrupt kernel memory on the same host that loaded the table. This stays within one kernel security authority and is not a VM escape or IOMMU bypass.\nC:H - An out-of-range seg_id makes CACHE_DEV_SEGMENT() point past the DAX mapping into kernel memory, and cache_seg_meta_load() copy_mc_to_kernel\u0027s that region; oversized n_segs also reads past the kvalloc\u0027d segments[] array. That kernel memory-corruption read primitive is Confidentiality High.\nI:H - cache_seg_init() writes pcache_cache_segment fields past the kvalloc\u0027d cache-\u003esegments[] when n_segs exceeds seg_num, and a wild CACHE_DEV_SEGMENT() is later written through memcpy_flushcache/memset. That out-of-bounds kernel write is Integrity High and exploitable for code execution.\nA:H - Heap overflow of cache-\u003esegments[] or dereference of a mapping-relative pointer past the DAX device causes a kernel oops or panic at table load, fully denying availability."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:45:46.216Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ab5dcde6fa96bc115b85f3621c60e39c66229a90"
        },
        {
          "url": "https://git.kernel.org/stable/c/3e19172089ec81132a8a48e802b1034a744209f4"
        },
        {
          "url": "https://git.kernel.org/stable/c/32d1809da31094ef76fd98dc1f1a8b55ca1295dd"
        }
      ],
      "title": "dm-pcache: validate geometry fields from on-disk cache_info",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80962",
    "datePublished": "2026-09-11T19:42:28.500Z",
    "dateReserved": "2026-08-26T14:34:25.809Z",
    "dateUpdated": "2026-10-19T08:45:46.216Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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