Vulnerability-Lookup

FKIE_CVE-2026-43067

Vulnerability from fkie_nvd - Published: 2026-05-05 16:16 - Updated: 2026-05-20 23:16

Severity ?

9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: ext4: handle wraparound when searching for blocks for indirect mapped blocks Commit 4865c768b563 ("ext4: always allocate blocks only from groups inode can use") restricts what blocks will be allocated for indirect block based files to block numbers that fit within 32-bit block numbers. However, when using a review bot running on the latest Gemini LLM to check this commit when backporting into an LTS based kernel, it raised this concern: If ac->ac_g_ex.fe_group is >= ngroups (for instance, if the goal group was populated via stream allocation from s_mb_last_groups), then start will be >= ngroups. Does this allow allocating blocks beyond the 32-bit limit for indirect block mapped files? The commit message mentions that ext4_mb_scan_groups_linear() takes care to not select unsupported groups. However, its loop uses group = *start, and the very first iteration will call ext4_mb_scan_group() with this unsupported group because next_linear_group() is only called at the end of the iteration. After reviewing the code paths involved and considering the LLM review, I determined that this can happen when there is a file system where some files/directories are extent-mapped and others are indirect-block mapped. To address this, add a safety clamp in ext4_mb_scan_groups().

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/12624c5b724a81e14e532972b40d863b0de3b7d1	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2a368ccddfc492a0aa951e2caef2985f20e96503	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/4bec4a498ce86314d470ae6144120461f2138c29	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/83170a05908b6cf2fb3235d3065bf613ff866f3c	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/bb81702370fad22c06ca12b6e1648754dbc37e0f	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/f89bba144938921a2249237ad04a0183ff3f8930	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	6.1.167

JSON

To clipboard

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: handle wraparound when searching for blocks for indirect mapped blocks\n\nCommit 4865c768b563 (\"ext4: always allocate blocks only from groups\ninode can use\") restricts what blocks will be allocated for indirect\nblock based files to block numbers that fit within 32-bit block\nnumbers.\n\nHowever, when using a review bot running on the latest Gemini LLM to\ncheck this commit when backporting into an LTS based kernel, it raised\nthis concern:\n\n   If ac-\u003eac_g_ex.fe_group is \u003e= ngroups (for instance, if the goal\n   group was populated via stream allocation from s_mb_last_groups),\n   then start will be \u003e= ngroups.\n\n   Does this allow allocating blocks beyond the 32-bit limit for\n   indirect block mapped files? The commit message mentions that\n   ext4_mb_scan_groups_linear() takes care to not select unsupported\n   groups. However, its loop uses group = *start, and the very first\n   iteration will call ext4_mb_scan_group() with this unsupported\n   group because next_linear_group() is only called at the end of the\n   iteration.\n\nAfter reviewing the code paths involved and considering the LLM\nreview, I determined that this can happen when there is a file system\nwhere some files/directories are extent-mapped and others are\nindirect-block mapped.  To address this, add a safety clamp in\next4_mb_scan_groups()."
    }
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  "lastModified": "2026-05-20T23:16:20.980",
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          "baseScore": 9.8,
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          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
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        "type": "Secondary"
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      "source": "nvd@nist.gov",
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}

CVE-2026-43067 (GCVE-0-2026-43067)

Vulnerability from cvelistv5 – Published: 2026-05-05 15:23 – Updated: 2026-05-11 22:17

Title

ext4: handle wraparound when searching for blocks for indirect mapped blocks

Summary

Severity ?

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux

References

6 references

URL	Tags
https://git.kernel.org/stable/c/f89bba144938921a2…
https://git.kernel.org/stable/c/83170a05908b6cf2f…
https://git.kernel.org/stable/c/4bec4a498ce86314d…
https://git.kernel.org/stable/c/12624c5b724a81e14…
https://git.kernel.org/stable/c/2a368ccddfc492a0a…
https://git.kernel.org/stable/c/bb81702370fad22c0…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 9d89b9d55e25cb340c5b4b769876edc551b7a9ff , < f89bba144938921a2249237ad04a0183ff3f8930 (git) Affected: 1b0edd6022a3f44ce87fea9959a9310f4628fbea , < 83170a05908b6cf2fb3235d3065bf613ff866f3c (git) Affected: 9eea2f57d11b30049ff996ac3eff6e0dc8089e5f , < 4bec4a498ce86314d470ae6144120461f2138c29 (git) Affected: 34c803edc0b3365a42efcf9815acab63b4cf54e0 , < 12624c5b724a81e14e532972b40d863b0de3b7d1 (git) Affected: 321ed8d559c951e71ad2d2d69a4cf0445644e865 , < 2a368ccddfc492a0aa951e2caef2985f20e96503 (git) Affected: 4865c768b563deff1b6a6384e74a62f143427b42 , < bb81702370fad22c06ca12b6e1648754dbc37e0f (git) Affected: 16fce6b6c0b247258c6c217fce5a48abf50f6964 (git)
Linux	Linux	Affected: 6.1.167 , < 6.1.168 (semver) Affected: 6.6.130 , < 6.6.134 (semver) Affected: 6.12.77 , < 6.12.80 (semver) Affected: 6.18.14 , < 6.18.21 (semver) Affected: 6.19.4 , < 6.19.11 (semver)

Show details on NVD website

JSON

To clipboard

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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.

Action not permitted

FKIE_CVE-2026-43067

CVE-2026-43067 (GCVE-0-2026-43067)

Tags

Sightings

Nomenclature