CVE-2022-49343 (GCVE-0-2022-49343)
Vulnerability from cvelistv5
Published
2025-02-26 02:10
Modified
2026-08-05 08:54
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ext4: avoid cycles in directory h-tree A maliciously corrupted filesystem can contain cycles in the h-tree stored inside a directory. That can easily lead to the kernel corrupting tree nodes that were already verified under its hands while doing a node split and consequently accessing unallocated memory. Fix the problem by verifying traversed block numbers are unique.
References
Impacted products
Vendor Product Version
Linux Linux Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
Version: ac27a0ec112a089f1a5102bc8dffc79c8c815571
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ext4/namei.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
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          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.19"
            },
            {
              "lessThan": "2.6.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.14.*",
              "status": "unaffected",
              "version": "4.14.283",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.19.*",
              "status": "unaffected",
              "version": "4.19.247",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.4.*",
              "status": "unaffected",
              "version": "5.4.198",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.121",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.46",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.17.*",
              "status": "unaffected",
              "version": "5.17.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.18.*",
              "status": "unaffected",
              "version": "5.18.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.19",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.14.283",
                  "versionStartIncluding": "2.6.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.19.247",
                  "versionStartIncluding": "2.6.19",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.4.198",
                  "versionStartIncluding": "2.6.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.121",
                  "versionStartIncluding": "2.6.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.46",
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                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.17.14",
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                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "5.18.3",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.19",
                  "versionStartIncluding": "2.6.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: avoid cycles in directory h-tree\n\nA maliciously corrupted filesystem can contain cycles in the h-tree\nstored inside a directory. That can easily lead to the kernel corrupting\ntree nodes that were already verified under its hands while doing a node\nsplit and consequently accessing unallocated memory. Fix the problem by\nverifying traversed block numbers are unique."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached only through local VFS directory operations on a mounted crafted ext4 image (creat/mkdir \u2192 ext4_add_entry \u2192 ext4_dx_add_entry \u2192 dx_probe \u2192 do_split/index split); there is no network or adjacent-protocol entry into fs/ext4/namei.c.\nAC:L - The attacker fully controls on-disk h-tree block pointers, so a cyclic index (e.g. an intermediate node pointing back to an ancestor) deterministically makes dx_probe load the same block at multiple frame levels and then corrupts those nodes on split; no race or attacker-uncontrollable layout is required.\nPR:N - The attacker needs no account on the target\u2014only a malicious ext4 image (USB/SD, disk image, or media handed to udisks/automount); ext4 is FS_REQUIRES_DEV without FS_USERNS_MOUNT, so CAP_SYS_ADMIN for mount belongs to the victim or automount path.\nUI:R - Exploitation requires a user or automount/storage daemon to mount the attacker-supplied ext4 volume and then perform a directory write that triggers an h-tree node split on the cyclic directory.\nS:U - Corruption and crashes remain within the host kernel\u2019s buffer-cache/htree handling under the same OS security authority; this is standard local kernel impact, not a VM escape, IOMMU bypass, or other cross-boundary break.\nC:H - Node split on aliased frames corrupts already-verified index nodes and leads to accessing unallocated memory; that out-of-bounds/UAF-class read of kernel heap or freed buffers enables arbitrary disclosure and is scored Confidentiality High.\nI:H - The same split path (dx_insert_block/memmove and index-node rewrites through shared frame buffers) performs attacker-influenced writes into corrupted/unallocated memory, enabling heap corruption and control-flow hijack primitives scored Integrity High.\nA:H - Accessing unallocated memory during the split of a cyclic h-tree can oops/panic the kernel even without full exploitation, fully denying availability."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T08:54:50.163Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/24b8206fec1db21d7e82f21f0b2ff5e5672cf5b3"
        },
        {
          "url": "https://git.kernel.org/stable/c/b3ad9ff6f06c1dc6abf7437691c88ca3d6da3ac0"
        },
        {
          "url": "https://git.kernel.org/stable/c/e157c8f87e8fac112d6c955e69a60cdb9bc80a60"
        },
        {
          "url": "https://git.kernel.org/stable/c/ff4cafa51762da3824881a9000ca421d4b78b138"
        },
        {
          "url": "https://git.kernel.org/stable/c/3a3ce941645407cd0b0b7f01ad9e2ea3770f46cc"
        },
        {
          "url": "https://git.kernel.org/stable/c/d5a16a6df2c16eaf4de04948553ef0089dee463f"
        },
        {
          "url": "https://git.kernel.org/stable/c/6084240bfc44bf265ab6ae7d96980469b05be0f1"
        },
        {
          "url": "https://git.kernel.org/stable/c/3ba733f879c2a88910744647e41edeefbc0d92b2"
        }
      ],
      "title": "ext4: avoid cycles in directory h-tree",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2022-49343",
    "datePublished": "2025-02-26T02:10:59.970Z",
    "dateReserved": "2025-02-26T02:08:31.542Z",
    "dateUpdated": "2026-08-05T08:54:50.163Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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