CVE-2026-97520 (GCVE-0-2026-97520)
Vulnerability from cvelistv5
Published
2026-09-24 16:05
Modified
2026-09-28 05:30
Severity ?
7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: gfs2: move quota_init qc iterator increment Move qc++ from the loop body into the for-loop increment expression in gfs2_quota_init(). This keeps iterator progression explicit and avoids mixing pointer advance with duplicate-slot handling in the loop body.
References
Impacted products
Vendor Product Version
Linux Linux Version: de0d95c26c41c1776e4d23b1a8b3f2bcfd1dae5f
Version: de0d95c26c41c1776e4d23b1a8b3f2bcfd1dae5f
Version: de0d95c26c41c1776e4d23b1a8b3f2bcfd1dae5f
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/gfs2/quota.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "04ec2f3b29b3c8a59950b8816b5ebc8ba052808a",
              "status": "affected",
              "version": "de0d95c26c41c1776e4d23b1a8b3f2bcfd1dae5f",
              "versionType": "git"
            },
            {
              "lessThan": "21a50a9373adab35ffadf5cf59272dc99078170e",
              "status": "affected",
              "version": "de0d95c26c41c1776e4d23b1a8b3f2bcfd1dae5f",
              "versionType": "git"
            },
            {
              "lessThan": "942202677f8f2ee448a6a2feb06aeeaf520342e3",
              "status": "affected",
              "version": "de0d95c26c41c1776e4d23b1a8b3f2bcfd1dae5f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/gfs2/quota.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "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": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngfs2: move quota_init qc iterator increment\n\nMove qc++ from the loop body into the for-loop increment\nexpression in gfs2_quota_init().\n\nThis keeps iterator progression explicit and avoids mixing pointer\nadvance with duplicate-slot handling in the loop body."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The malformed bytes are on-disk struct gfs2_quota_change records in the per-node quota_change file. gfs2_quota_init() reads them via gfs2_meta_ra() from gfs2_get_tree()\u2192get_tree_bdev()\u2192gfs2_fill_super()\u2192gfs2_make_fs_rw(); no NFS/SMB/TCP message carries qc_id or qc_change.\nAC:L - A crafted quota_change file with two non-zero qc_change entries sharing qc_id, the duplicate in the last slot of a QC block, makes the pre-fix body qc++ then memset(qc,0,sizeof(*qc)) run on every read-write mount of that image, with no race.\nPR:N - Crafting the image needs no host account. gfs2_fs_type.fs_flags is only FS_REQUIRES_DEV (no FS_USERNS_MOUNT), so mount_capable() is capable(CAP_SYS_ADMIN) in init_user_ns; that privileged mount of the attacker image is scored as UI:R, not attacker privilege.\nUI:R - gfs2_quota_init() runs only from gfs2_make_fs_rw() after gfs2_fill_super() or gfs2_reconfigure() attaches the attacker-supplied block device. Because gfs2 is not FS_USERNS_MOUNT, a victim or administrator must mount that image read-write before the duplicate-slot memset runs.\nS:U - The out-of-bounds memset in gfs2_quota_init() corrupts page-cache memory in the host kernel that mounted the volume; this is not a KVM/Xen guest-to-host escape or an IOMMU/DMA bypass.\nC:N - The duplicate path only stores 16 zeros through the already-advanced qc pointer; it does not load adjacent kernel bytes or copy them to userspace.\nI:H - Pre-fix, qc++ runs before memset(qc,0,sizeof(*qc)). sd_qc_per_block is (sb_bsize-24)/16, leaving 8 bytes of padding, so a last-slot duplicate stores 8 zeros past bh-\u003eb_data+sb_bsize of the gfs2_getbuf() buffer_head: a kernel out-of-bounds write.\nA:H - Those 8 zeros past the QC buffer_head land in the next folio/page (or the next BH in the same folio when sb_bsize\u003cPAGE_SIZE) and can oops the kernel when that memory is live, poisoned, or KASAN-guarded."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-28T05:30:58.172Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/04ec2f3b29b3c8a59950b8816b5ebc8ba052808a"
        },
        {
          "url": "https://git.kernel.org/stable/c/21a50a9373adab35ffadf5cf59272dc99078170e"
        },
        {
          "url": "https://git.kernel.org/stable/c/942202677f8f2ee448a6a2feb06aeeaf520342e3"
        }
      ],
      "title": "gfs2: move quota_init qc iterator increment",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97520",
    "datePublished": "2026-09-24T16:05:20.188Z",
    "dateReserved": "2026-09-24T16:01:01.152Z",
    "dateUpdated": "2026-09-28T05:30:58.172Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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