cve-2026-31449

HIGH CVSS 7.8 nvd
Description

In the Linux kernel, the following vulnerability has been resolved: ext4: validate p_idx bounds in ext4_ext_correct_indexes ext4_ext_correct_indexes() walks up the extent tree correcting index entries when the first extent in a leaf is modified. Before accessing path[k].p_idx->ei_block, there is no validation that p_idx falls within the valid range of index entries for that level. If the on-disk extent header contains a corrupted or crafted eh_entries value, p_idx can point past the end of the allocated buffer, causing a slab-out-of-bounds read. Fix this by validating path[k].p_idx against EXT_LAST_INDEX() at both access sites: before the while loop and inside it. Return -EFSCORRUPTED if the index pointer is out of range, consistent with how other bounds violations are handled in the ext4 extent tree code.

Timeline
Published
2026-04-22
Last Modified
2026-09-08
CVSS Details
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
Affected Products
  • linux linux_kernel
Weaknesses (CWE)
CWE-125
CVSS metrics
Version Base Severity Vector Exploitability Impact Source
3.1 7.8 HIGH CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H 1.8 5.9 416baaa9-dc9f-4396-8d5f-8c081fb06d67
CPE configurations
OR
CPE Version range Vulnerable
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* >= 2.6.19.1, < 6.12.80 yes
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* >= 6.13, < 6.18.21 yes
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* >= 6.19, < 6.19.11 yes
cpe:2.3:o:linux:linux_kernel:2.6.19:-:*:*:*:*:*:* — yes
cpe:2.3:o:linux:linux_kernel:2.6.19:rc2:*:*:*:*:*:* — yes
cpe:2.3:o:linux:linux_kernel:2.6.19:rc3:*:*:*:*:*:* — yes
cpe:2.3:o:linux:linux_kernel:2.6.19:rc4:*:*:*:*:*:* — yes
cpe:2.3:o:linux:linux_kernel:2.6.19:rc5:*:*:*:*:*:* — yes
cpe:2.3:o:linux:linux_kernel:2.6.19:rc6:*:*:*:*:*:* — yes
cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* — yes
cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* — yes
cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* — yes
cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* — yes
cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* — yes
NVD metadata
NVD status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
Linked Vulnerabilities
alas2023-2026-1646 amazon_linux
alas2023-2026-1746 amazon_linux
alas2023-2026-1752 amazon_linux
alas2kernel-5.10-2026-124 amazon_linux
alas2kernel-5.15-2026-110 amazon_linux
azurelinux3-83273 azure_linux
elsa-2026-50372 oracle_linux
oracle-2026500163 oracle_linux 

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  "datePublished": "2026-04-22T14:16:38.933",
  "dateUpdated": "2026-09-08T09:17:55.763",
  "description": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: validate p_idx bounds in ext4_ext_correct_indexes\n\next4_ext_correct_indexes() walks up the extent tree correcting\nindex entries when the first extent in a leaf is modified. Before\naccessing path[k].p_idx->ei_block, there is no validation that\np_idx falls within the valid range of index entries for that\nlevel.\n\nIf the on-disk extent header contains a corrupted or crafted\neh_entries value, p_idx can point past the end of the allocated\nbuffer, causing a slab-out-of-bounds read.\n\nFix this by validating path[k].p_idx against EXT_LAST_INDEX() at\nboth access sites: before the while loop and inside it. Return\n-EFSCORRUPTED if the index pointer is out of range, consistent\nwith how other bounds violations are handled in the ext4 extent\ntree code.",
  "id": "CVE-2026-31449",
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    "cveTags": [],
    "descriptions": [
      {
        "lang": "en",
        "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: validate p_idx bounds in ext4_ext_correct_indexes\n\next4_ext_correct_indexes() walks up the extent tree correcting\nindex entries when the first extent in a leaf is modified. Before\naccessing path[k].p_idx->ei_block, there is no validation that\np_idx falls within the valid range of index entries for that\nlevel.\n\nIf the on-disk extent header contains a corrupted or crafted\neh_entries value, p_idx can point past the end of the allocated\nbuffer, causing a slab-out-of-bounds read.\n\nFix this by validating path[k].p_idx against EXT_LAST_INDEX() at\nboth access sites: before the while loop and inside it. Return\n-EFSCORRUPTED if the index pointer is out of range, consistent\nwith how other bounds violations are handled in the ext4 extent\ntree code."
      }
    ],
    "id": "CVE-2026-31449",
    "lastModified": "2026-09-08T09:17:55.763",
    "metrics": {
      "cvssMetricV31": [
        {
          "cvssData": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
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          "type": "Secondary"
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    "published": "2026-04-22T14:16:38.933",
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        "source": "nvd@nist.gov",
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  },
  "severity": "HIGH",
  "source": "nvd",
  "title": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: validate p_idx bounds in ext4_ext_correct_..."
}
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