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

Vulnerability from cvelistv5 – Published: 2026-05-05 15:23 – Updated: 2026-05-11 22:17
VLAI?
Title
ext4: handle wraparound when searching for blocks for indirect mapped blocks
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().
Severity ?
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted 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)
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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)
Create a notification for this product.
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}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.