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CVE-2026-80959 (GCVE-0-2026-80959)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:42 – Updated: 2026-09-13 06:28
VLAI
Title
dm-pcache: bound the persisted tail-position offset
Summary
In the Linux kernel, the following vulnerability has been resolved: dm-pcache: bound the persisted tail-position offset cache_pos_decode() takes the persisted key_tail and dirty_tail seg_off from the cache device and addresses within the segment with it. A seg_off at or past the segment data_size, controllable by whoever supplies the device (CAP_SYS_ADMIN), reads past the segment data. Reject a decoded seg_off that is not below the segment data_size.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 , < ffd9a214a94f9928e54856f42b1cc3e33fb10e36 (git)
Affected: 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 , < 8bf7a06ca3c1611809725f58cfd573f2ffbda75f (git)
Affected: 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 , < d1898576090a10d2ac2715218a652e78fb65a6b0 (git)
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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.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ffd9a214a94f9928e54856f42b1cc3e33fb10e36",
              "status": "affected",
              "version": "1d57628ff95b32d5cfa8d8f50e07690c161e9cf0",
              "versionType": "git"
            },
            {
              "lessThan": "8bf7a06ca3c1611809725f58cfd573f2ffbda75f",
              "status": "affected",
              "version": "1d57628ff95b32d5cfa8d8f50e07690c161e9cf0",
              "versionType": "git"
            },
            {
              "lessThan": "d1898576090a10d2ac2715218a652e78fb65a6b0",
              "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-rc1",
              "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-rc1",
                  "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: bound the persisted tail-position offset\n\ncache_pos_decode() takes the persisted key_tail and dirty_tail seg_off from\nthe cache device and addresses within the segment with it. A seg_off at or\npast the segment data_size, controllable by whoever supplies the device\n(CAP_SYS_ADMIN), reads past the segment data.\n\nReject a decoded seg_off that is not below the segment data_size."
        }
      ],
      "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 unbounded tail offset is consumed only when a local caller loads a dm-pcache table (ctl_ioctl \u2192 table_load \u2192 dm_pcache_ctr \u2192 pcache_cache_start \u2192 cache_tail_init \u2192 cache_pos_decode) from a supplied DAX cache device; no network, Bluetooth, or USB receive path parses this metadata.\nAC:L - The attacker fully controls the cache device and can forge key_tail/dirty_tail pos_onmedia with a valid CRC (public PCACHE_CRC_SEED), so cache_pos_decode() deterministically accepts an out-of-range seg_off; no race or uninfluenced victim state is required.\nPR:L - dm-ioctl.c gates table load with capable(CAP_SYS_ADMIN); kernel-CNA scoring treats that delegated capability (privileged containers, LVM/storage helpers) as Low rather than exclusive init-namespace root, and the attacker supplies the cache/backing devices on the pcache table.\nUI:N - The attacker performs every step itself: craft the persisted tail positions on a DAX cache device and issue DM_TABLE_LOAD for a pcache target; no other user must mount media, open files, or otherwise interact.\nS:U - The out-of-bounds pmem/kernel access and resulting oops stay inside the host kernel device-mapper/pcache mapping; this is not a VM escape, IOMMU bypass, or other cross-authority boundary.\nC:H - cache_replay(), writeback and GC copy ksets via copy_mc_to_kernel from cache_pos_addr() (segment.data plus the attacker-controlled u32 seg_off) for up to PCACHE_KSET_ONMEDIA_SIZE_MAX bytes, an unbounded over-read past segment data into later pmem or adjacent kernel VA, not a few-byte leak.\nI:H - A seg_off at data_size makes append_last_kset() memcpy_flushcache a kset into the next 16MiB segment\u0027s control metadata; a larger seg_off underflows u32 cache_seg_remain() so later key-head writes become arbitrary-offset stores through the DAX mapping, an out-of-bounds write primitive.\nA:H - cache_pos_advance() hits BUG_ON(cache_seg_remain(pos) \u003c len) when a tail sits at data_size, and a huge seg_off makes copy_mc_to_kernel/memcpy_flushcache walk off the DAX mapping into unmapped kernel VA, oopsing or panicking the host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-13T06:28:31.649Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ffd9a214a94f9928e54856f42b1cc3e33fb10e36"
        },
        {
          "url": "https://git.kernel.org/stable/c/8bf7a06ca3c1611809725f58cfd573f2ffbda75f"
        },
        {
          "url": "https://git.kernel.org/stable/c/d1898576090a10d2ac2715218a652e78fb65a6b0"
        }
      ],
      "title": "dm-pcache: bound the persisted tail-position offset",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80959",
    "datePublished": "2026-09-11T19:42:26.514Z",
    "dateReserved": "2026-08-26T14:34:25.809Z",
    "dateUpdated": "2026-09-13T06:28:31.649Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
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      "date": "2026-09-18",
      "epss": "0.00127",
      "percentile": "0.02719"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "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": [
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              },
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                ],
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                "vendor": "Linux",
                "versions": [
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                    "status": "unaffected",
                    "version": "7.2.4",
                    "versionType": "semver"
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                    "status": "unaffected",
                    "version": "7.3-rc1",
                    "versionType": "original_commit_for_fix"
                  }
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              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm-pcache: bound the persisted tail-position offset\n\ncache_pos_decode() takes the persisted key_tail and dirty_tail seg_off from\nthe cache device and addresses within the segment with it. A seg_off at or\npast the segment data_size, controllable by whoever supplies the device\n(CAP_SYS_ADMIN), reads past the segment data.\n\nReject a decoded seg_off that is not below the segment data_size."
          }
        ],
        "id": "CVE-2026-80959",
        "lastModified": "2026-09-13T07:17:02.943",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-09-11T20:19:01.750",
        "references": [
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            "url": "https://git.kernel.org/stable/c/8bf7a06ca3c1611809725f58cfd573f2ffbda75f"
          },
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/d1898576090a10d2ac2715218a652e78fb65a6b0"
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-14T17:36:25+00:00",
      "cve": "CVE-2026-80959",
      "id": "CVE-2026-80959",
      "initial_release_date": "2026-09-11T00:00:00+00:00",
      "product_status:known_not_affected": "276",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: dm-pcache: bound the persisted tail-position offset",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80959.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-15T01:05:25Z",
      "cve": "CVE-2026-80959",
      "id": "CVE-2026-80959",
      "initial_release_date": "2026-09-12T16:36:55Z",
      "product_status:known_not_affected": "353",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-80959",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-80959.json",
      "version": "4"
    }
  }
}



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  • 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.
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  • 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.


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