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

Vulnerability from cvelistv5 – Published: 2026-05-05 15:23 – Updated: 2026-08-05 12:25
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)
Affected: 5.15.203 , < 5.16 (semver)
Create a notification for this product.
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.
Show details on NVD website
To clipboard 

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      "cve": "CVE-2026-43067",
      "id": "CVE-2026-43067",
      "initial_release_date": "2026-05-05T00:00:00+00:00",
      "product_status:known_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ext4: handle wraparound when searching for blocks for indirect mapped blocks",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43067.json",
      "version": "3"
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}



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Tags
Taxonomy of the tags.





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.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.