Vulnerability-Lookup

GHSA-PQWG-4RRM-3FG7

Vulnerability from github – Published: 2026-05-27 15:33 – Updated: 2026-05-27 15:33

Details

In the Linux kernel, the following vulnerability has been resolved:

ext4: don't zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1

When allocating initialized blocks from a large unwritten extent, or when splitting an unwritten extent during end I/O and converting it to initialized, there is currently a potential issue of stale data if the extent needs to be split in the middle.

   0  A      B  N
   [UUUUUUUUUUUU]    U: unwritten extent
   [--DDDDDDDD--]    D: valid data
      |<-  ->| ----> this range needs to be initialized

ext4_split_extent() first try to split this extent at B with EXT4_EXT_DATA_ENTIRE_VALID1 and EXT4_EXT_MAY_ZEROOUT flag set, but ext4_split_extent_at() failed to split this extent due to temporary lack of space. It zeroout B to N and mark the entire extent from 0 to N as written.

   0  A      B  N
   [WWWWWWWWWWWW]    W: written extent
   [SSDDDDDDDDZZ]    Z: zeroed, S: stale data

ext4_split_extent() then try to split this extent at A with EXT4_EXT_DATA_VALID2 flag set. This time, it split successfully and left a stale written extent from 0 to A.

   0  A      B   N
   [WW|WWWWWWWWWW]
   [SS|DDDDDDDDZZ]

Fix this by pass EXT4_EXT_DATA_PARTIAL_VALID1 to ext4_split_extent_at() when splitting at B, don't convert the entire extent to written and left it as unwritten after zeroing out B to N. The remaining work is just like the standard two-part split. ext4_split_extent() will pass the EXT4_EXT_DATA_VALID2 flag when it calls ext4_split_extent_at() for the second time, allowing it to properly handle the split. If the split is successful, it will keep extent from 0 to A as unwritten.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-45858"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-27T14:16:57Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: don\u0027t zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1\n\nWhen allocating initialized blocks from a large unwritten extent, or\nwhen splitting an unwritten extent during end I/O and converting it to\ninitialized, there is currently a potential issue of stale data if the\nextent needs to be split in the middle.\n\n       0  A      B  N\n       [UUUUUUUUUUUU]    U: unwritten extent\n       [--DDDDDDDD--]    D: valid data\n          |\u003c-  -\u003e| ----\u003e this range needs to be initialized\n\next4_split_extent() first try to split this extent at B with\nEXT4_EXT_DATA_ENTIRE_VALID1 and EXT4_EXT_MAY_ZEROOUT flag set, but\next4_split_extent_at() failed to split this extent due to temporary lack\nof space. It zeroout B to N and mark the entire extent from 0 to N\nas written.\n\n       0  A      B  N\n       [WWWWWWWWWWWW]    W: written extent\n       [SSDDDDDDDDZZ]    Z: zeroed, S: stale data\n\next4_split_extent() then try to split this extent at A with\nEXT4_EXT_DATA_VALID2 flag set. This time, it split successfully and left\na stale written extent from 0 to A.\n\n       0  A      B   N\n       [WW|WWWWWWWWWW]\n       [SS|DDDDDDDDZZ]\n\nFix this by pass EXT4_EXT_DATA_PARTIAL_VALID1 to ext4_split_extent_at()\nwhen splitting at B, don\u0027t convert the entire extent to written and left\nit as unwritten after zeroing out B to N. The remaining work is just\nlike the standard two-part split. ext4_split_extent() will pass the\nEXT4_EXT_DATA_VALID2 flag when it calls ext4_split_extent_at() for the\nsecond time, allowing it to properly handle the split. If the split is\nsuccessful, it will keep extent from 0 to A as unwritten.",
  "id": "GHSA-pqwg-4rrm-3fg7",
  "modified": "2026-05-27T15:33:13Z",
  "published": "2026-05-27T15:33:13Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45858"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1bf6974822d1dba86cf11b5f05498581cf3488a2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/58ddae5d77b1db3a27b891c75a8fa120239ac092"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7015fcf473796e1d2d876f241bd9e0c36f3d4eef"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d17857b4fb9ba5745b59be0ef38fd532991fccbf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d67c8ecf3d8fda9b8ef80e6f665d84b6d6ac9d88"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-45858 (GCVE-0-2026-45858)

Vulnerability from cvelistv5 – Published: 2026-05-27 12:15 – Updated: 2026-05-27 12:15

Title

ext4: don't zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1

Summary

In the Linux kernel, the following vulnerability has been resolved: ext4: don't zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1 When allocating initialized blocks from a large unwritten extent, or when splitting an unwritten extent during end I/O and converting it to initialized, there is currently a potential issue of stale data if the extent needs to be split in the middle. 0 A B N [UUUUUUUUUUUU] U: unwritten extent [--DDDDDDDD--] D: valid data |<- ->| ----> this range needs to be initialized ext4_split_extent() first try to split this extent at B with EXT4_EXT_DATA_ENTIRE_VALID1 and EXT4_EXT_MAY_ZEROOUT flag set, but ext4_split_extent_at() failed to split this extent due to temporary lack of space. It zeroout B to N and mark the entire extent from 0 to N as written. 0 A B N [WWWWWWWWWWWW] W: written extent [SSDDDDDDDDZZ] Z: zeroed, S: stale data ext4_split_extent() then try to split this extent at A with EXT4_EXT_DATA_VALID2 flag set. This time, it split successfully and left a stale written extent from 0 to A. 0 A B N [WW|WWWWWWWWWW] [SS|DDDDDDDDZZ] Fix this by pass EXT4_EXT_DATA_PARTIAL_VALID1 to ext4_split_extent_at() when splitting at B, don't convert the entire extent to written and left it as unwritten after zeroing out B to N. The remaining work is just like the standard two-part split. ext4_split_extent() will pass the EXT4_EXT_DATA_VALID2 flag when it calls ext4_split_extent_at() for the second time, allowing it to properly handle the split. If the split is successful, it will keep extent from 0 to A as unwritten.

Severity

No CVSS data available.

Assigner

Linux

References

5 references

URL	Tags
https://git.kernel.org/stable/c/58ddae5d77b1db3a2…
https://git.kernel.org/stable/c/d17857b4fb9ba5745…
https://git.kernel.org/stable/c/d67c8ecf3d8fda9b8…
https://git.kernel.org/stable/c/7015fcf473796e1d2…
https://git.kernel.org/stable/c/1bf6974822d1dba86…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 58ddae5d77b1db3a27b891c75a8fa120239ac092 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < d17857b4fb9ba5745b59be0ef38fd532991fccbf (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < d67c8ecf3d8fda9b8ef80e6f665d84b6d6ac9d88 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 7015fcf473796e1d2d876f241bd9e0c36f3d4eef (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 1bf6974822d1dba86cf11b5f05498581cf3488a2 (git) Affected: 0 , < 6.6.130 (semver) Affected: 0 , < 6.12.75 (semver) Affected: 0 , < 6.18.14 (semver) Affected: 0 , < 6.19.4 (semver)
Linux	Linux	Unaffected: 6.6.130 , ≤ 6.6.* (semver) Unaffected: 6.12.75 , ≤ 6.12.* (semver) Unaffected: 6.18.14 , ≤ 6.18.* (semver) Unaffected: 6.19.4 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix)

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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ext4/extents.c"
          ],
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          "vendor": "Linux",
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              "status": "affected",
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              "version": "0",
              "versionType": "semver"
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              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
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              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
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              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.130",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.75",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.130",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.75",
                  "vulnerable": true
                },
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                {
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                  "versionEndExcluding": "7.0",
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                }
              ],
              "negate": false,
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: don\u0027t zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1\n\nWhen allocating initialized blocks from a large unwritten extent, or\nwhen splitting an unwritten extent during end I/O and converting it to\ninitialized, there is currently a potential issue of stale data if the\nextent needs to be split in the middle.\n\n       0  A      B  N\n       [UUUUUUUUUUUU]    U: unwritten extent\n       [--DDDDDDDD--]    D: valid data\n          |\u003c-  -\u003e| ----\u003e this range needs to be initialized\n\next4_split_extent() first try to split this extent at B with\nEXT4_EXT_DATA_ENTIRE_VALID1 and EXT4_EXT_MAY_ZEROOUT flag set, but\next4_split_extent_at() failed to split this extent due to temporary lack\nof space. It zeroout B to N and mark the entire extent from 0 to N\nas written.\n\n       0  A      B  N\n       [WWWWWWWWWWWW]    W: written extent\n       [SSDDDDDDDDZZ]    Z: zeroed, S: stale data\n\next4_split_extent() then try to split this extent at A with\nEXT4_EXT_DATA_VALID2 flag set. This time, it split successfully and left\na stale written extent from 0 to A.\n\n       0  A      B   N\n       [WW|WWWWWWWWWW]\n       [SS|DDDDDDDDZZ]\n\nFix this by pass EXT4_EXT_DATA_PARTIAL_VALID1 to ext4_split_extent_at()\nwhen splitting at B, don\u0027t convert the entire extent to written and left\nit as unwritten after zeroing out B to N. The remaining work is just\nlike the standard two-part split. ext4_split_extent() will pass the\nEXT4_EXT_DATA_VALID2 flag when it calls ext4_split_extent_at() for the\nsecond time, allowing it to properly handle the split. If the split is\nsuccessful, it will keep extent from 0 to A as unwritten."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-27T12:15:37.738Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        },
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          "url": "https://git.kernel.org/stable/c/7015fcf473796e1d2d876f241bd9e0c36f3d4eef"
        },
        {
          "url": "https://git.kernel.org/stable/c/1bf6974822d1dba86cf11b5f05498581cf3488a2"
        }
      ],
      "title": "ext4: don\u0027t zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1",
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        "engine": "bippy-1.2.0"
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-45858",
    "datePublished": "2026-05-27T12:15:37.738Z",
    "dateReserved": "2026-05-13T15:03:33.079Z",
    "dateUpdated": "2026-05-27T12:15:37.738Z",
    "state": "PUBLISHED"
  },
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

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GHSA-PQWG-4RRM-3FG7

CVE-2026-45858 (GCVE-0-2026-45858)

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Nomenclature