CVE-2026-80958 (GCVE-0-2026-80958)
Vulnerability from cvelistv5
Published
2026-09-11 19:42
Modified
2026-10-19 08:45
Severity ?
7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: dm-pcache: clamp the tail kset read to the segment data region The tail-kset read in cache_replay(), the writeback worker and the GC worker bounds its length by PCACHE_SEG_SIZE - seg_off, the raw segment size rather than the data region. A tail near the segment end reads past the segment data into the following control area. Clamp the read to cache_seg_remain(), the data region.
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_gc.c",
            "drivers/md/dm-pcache/cache_key.c",
            "drivers/md/dm-pcache/cache_writeback.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2cd9776fe3f2d88ec22c36d3c8ba09fbf9d5500c",
              "status": "affected",
              "version": "1d57628ff95b32d5cfa8d8f50e07690c161e9cf0",
              "versionType": "git"
            },
            {
              "lessThan": "1ab55354368d071ebaee4d8c82313955eab65a04",
              "status": "affected",
              "version": "1d57628ff95b32d5cfa8d8f50e07690c161e9cf0",
              "versionType": "git"
            },
            {
              "lessThan": "becf07e2b0053027495ecd671b1f82fb2e615f68",
              "status": "affected",
              "version": "1d57628ff95b32d5cfa8d8f50e07690c161e9cf0",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/md/dm-pcache/cache_gc.c",
            "drivers/md/dm-pcache/cache_key.c",
            "drivers/md/dm-pcache/cache_writeback.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: clamp the tail kset read to the segment data region\n\nThe tail-kset read in cache_replay(), the writeback worker and the GC\nworker bounds its length by PCACHE_SEG_SIZE - seg_off, the raw segment\nsize rather than the data region. A tail near the segment end reads past\nthe segment data into the following control area.\n\nClamp the read to cache_seg_remain(), the data region."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The over-read is reached only through local device-mapper ioctls on /dev/mapper/control (ctl_ioctl requires CAP_SYS_ADMIN, then table_load \u2192 dm_pcache_ctr \u2192 pcache_cache_start \u2192 cache_replay), and later via the writeback and GC workers on that mapped device; no network, Bluetooth, or physical-bus input reaches the kset copy.\nAC:L - An attacker who supplies a crafted DAX/pmem cache image fully controls the persisted key_tail and dirty_tail, so placing a tail near the segment end deterministically copies past data_size; no race, heap layout, or other victim state outside attacker control is required.\nPR:L - dm-ioctl.c gates table load with capable(CAP_SYS_ADMIN), which user-namespace and privileged-container administrators satisfy without init-namespace root; the attacker can attach a DAX cache device they control and load the pcache table themselves.\nUI:N - Exploitation requires only the attacker\u0027s own dmsetup/DM_TABLE_LOAD of a crafted pcache cache device; no separate victim must mount media, open files, or take any other action.\nS:U - The out-of-bounds kset read and any resulting kernel oops remain inside the host kernel device-mapper/pcache subsystem; this is not a VM escape, IOMMU bypass, or other cross-authority breakout.\nC:H - copy_mc_to_kernel() copies up to PCACHE_KSET_ONMEDIA_SIZE_MAX (~5 KiB) past segment data_size into the next segment\u0027s control area, and on the last segment that continues beyond the DAX mapping into adjacent kernel memory; out-of-bounds reads are High unless limited to a few bytes.\nI:N - The destination is a correctly sized kset buffer (kzalloc or the writeback/GC scratch arrays); this is a source over-read, not an out-of-bounds write, use-after-free, or other kernel-memory corruption or control-flow hijack primitive.\nA:H - Reading past the last DAX-mapped page hits a vmap guard or unmapped hole and oopses the kernel, and a CRC-valid kset assembled across the data/control boundary that is larger than cache_seg_remain() hits BUG_ON in cache_pos_advance(), crashing the host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:45:42.221Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2cd9776fe3f2d88ec22c36d3c8ba09fbf9d5500c"
        },
        {
          "url": "https://git.kernel.org/stable/c/1ab55354368d071ebaee4d8c82313955eab65a04"
        },
        {
          "url": "https://git.kernel.org/stable/c/becf07e2b0053027495ecd671b1f82fb2e615f68"
        }
      ],
      "title": "dm-pcache: clamp the tail kset read to the segment data region",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80958",
    "datePublished": "2026-09-11T19:42:25.861Z",
    "dateReserved": "2026-08-26T14:34:25.809Z",
    "dateUpdated": "2026-10-19T08:45:42.221Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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