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CVE-2026-43068 Linux CVE debrief

CVE-2026-43068 is a Linux kernel ext4 issue where delayed block allocation can fail when the allocator keeps targeting a corrupted block group. The reported symptom is repeated allocation failures followed by ext4 warnings that data may be lost. NVD rates the issue MEDIUM (CVSS 5.5) because it is locally reachable and can disrupt availability.

Vendor
Linux
Product
Unknown
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-05
Original CVE updated
2026-05-20
Advisory published
2026-05-05
Advisory updated
2026-05-20

Who should care

Linux kernel maintainers, distribution kernel teams, and administrators running ext4 on affected kernel versions should care, especially where filesystem corruption or recovery scenarios are possible.

Technical summary

The report says ext4_mb_find_by_goal() can end up allocating from a block group already marked corrupted. After the bitmap-read path was changed to return real error codes, ext4_mb_load_buddy() may fail before the later corruption check is reached, so the allocator can return an error instead of skipping the bad group. NVD classifies the impact as availability-only, with local access required and no user interaction.

Defensive priority

Medium

Recommended defensive actions

  • Apply the relevant stable kernel fixes referenced by NVD for your supported kernel line.
  • Prioritize updates on systems that rely on ext4 and are exposed to filesystem corruption or repeated allocation errors.
  • Watch kernel logs for repeated ext4 delayed block allocation failures and related corruption messages.
  • If a system shows these errors, follow normal filesystem recovery and integrity-check procedures before returning it to service.
  • Confirm your deployed kernel falls within one of the affected version ranges listed by NVD.

Evidence notes

CVE publishedAt is 2026-05-05T16:16:16.053Z and modifiedAt is 2026-05-20T23:09:44.863Z. The source description includes repeated EXT4-fs delayed allocation failures and states that blocks are always requested from the corrupted block group. NVD lists affected Linux kernel ranges from 3.12 through multiple maintained branches up to the stated fixed versions, plus 7.0 release candidates. NVD also lists patch references on git.kernel.org.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-43068 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-43068

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-43068 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-43068

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/0b84571c886719823d537f05f4f07cad6357c4b7

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/1895f7904be71c48f1e6f338b28f24dabd6b8aeb

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/1c0d7c4cde38a887c6d74e0c89ddb25226943c78

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/2d31a5073f86a177edf44015e0dedb0c47cfd6d8

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/46066e3a06647c5b186cc6334409722622d05c44

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/9370207b36d26e45a8c8ef0500706d37036edd6b

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/fea6b2e250ff48f10d166011b57a8516ae5438c9

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.