CVE-2026-53174 (GCVE-0-2026-53174)
Vulnerability from cvelistv5
Published
2026-06-25 08:38
Modified
2026-08-05 12:33
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: ovl: keep err zero after successful ovl_cache_get() ovl_iterate_merged() stores PTR_ERR(cache) in err before checking IS_ERR(cache). On success err holds the truncated cache pointer and can be returned as a bogus non-zero error. The syzbot reproducer reaches this through overlay-on-overlay readdir: getdents64 iterate_dir(outer overlay file) ovl_iterate_merged() ovl_cache_get() ovl_dir_read_merged() ovl_dir_read() iterate_dir(inner overlay file) ovl_iterate_merged() Only compute PTR_ERR(cache) on the error path.
References
Impacted products
Vendor Product Version
Linux Linux Version: d25e4b739f8378419f990983f2542160e79738c5
Version: d25e4b739f8378419f990983f2542160e79738c5
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/overlayfs/readdir.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e7051909a01bfb883bfa78b27514854068ac4b85",
              "status": "affected",
              "version": "d25e4b739f8378419f990983f2542160e79738c5",
              "versionType": "git"
            },
            {
              "lessThan": "1711b6ed6953cee5940ca4c3a6e77f1b3798cee2",
              "status": "affected",
              "version": "d25e4b739f8378419f990983f2542160e79738c5",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/overlayfs/readdir.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.19"
            },
            {
              "lessThan": "6.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.13",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\novl: keep err zero after successful ovl_cache_get()\n\novl_iterate_merged() stores PTR_ERR(cache) in err before checking\nIS_ERR(cache). On success err holds the truncated cache pointer and\ncan be returned as a bogus non-zero error.\n\nThe syzbot reproducer reaches this through overlay-on-overlay readdir:\n\n  getdents64\n    iterate_dir(outer overlay file)\n      ovl_iterate_merged()\n        ovl_cache_get()\n          ovl_dir_read_merged()\n            ovl_dir_read()\n              iterate_dir(inner overlay file)\n                ovl_iterate_merged()\n\nOnly compute PTR_ERR(cache) on the error path."
        }
      ],
      "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 vulnerable path is reached through local filesystem syscalls, specifically opening/enumerating nested overlayfs directories with getdents/getdents64. It is not reachable from network packets or adjacent/physical input.\nAC:L - The attacker controls the overlay-on-overlay setup and the readdir/getdents trigger, and syzbot demonstrated reproducible crashes. Any pointer-value dependency can be retried or influenced with local heap grooming, so no uncontrollable race or victim state is required.\nPR:L - Creating the crafted overlayfs setup requires local privileges, but overlayfs is marked FS_USERNS_MOUNT and is reachable in a user namespace on systems allowing unprivileged user namespaces. Thus a basic local user is sufficient in the highest reasonable deployment scenario.\nUI:N - No victim action is needed once the attacker has local execution; the attacker mounts/prepares the nested overlay and invokes getdents directly. The vulnerable code runs synchronously in the attacker\u0027s syscall path.\nS:U - The impact remains within the kernel and the local system security authority. This is not a VM escape, IOMMU bypass, or cross-scope boundary violation.\nC:H - The bug can convert a successful overlay directory-cache pointer into a bogus cache pointer and produce wild memory access in ovl_seek_cursor/ovl_iterate. On severe but reasonable architectures/configurations this can amount to stale/truncated kernel-pointer use, so kernel memory disclosure is defensible.\nI:H - The same wild-pointer/UAF-style path can cause overlayfs to interpret invalid or attacker-influenced memory as ovl_cache_entry state and perform cache-entry updates through it. Given the kernel memory corruption primitive and uncertainty, high integrity impact is the safer defensible choice.\nA:H - The public syzbot report is a general protection fault/Oops with KASAN wild-memory-access in ovl_iterate, reachable from getdents. A local attacker can repeatedly trigger this path to crash or panic affected kernels."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:33:43.620Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e7051909a01bfb883bfa78b27514854068ac4b85"
        },
        {
          "url": "https://git.kernel.org/stable/c/1711b6ed6953cee5940ca4c3a6e77f1b3798cee2"
        }
      ],
      "title": "ovl: keep err zero after successful ovl_cache_get()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-53174",
    "datePublished": "2026-06-25T08:38:51.366Z",
    "dateReserved": "2026-06-09T07:44:35.389Z",
    "dateUpdated": "2026-08-05T12:33:43.620Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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