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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 CPE status
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)
guessed 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)
guessed Create a notification for this product.
Show details on NVD website
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    "redhat_vex": {
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      "current_release_date": "2026-07-03T14:57:28+00:00",
      "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"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-06T01:21:48Z",
      "cve": "CVE-2026-43067",
      "id": "CVE-2026-43067",
      "initial_release_date": "2026-05-06T01:40:35Z",
      "product_status:known_not_affected": "293",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-43067",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-43067.json",
      "version": "5"
    }
  }
}



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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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