CVE-2026-43067: Linux kernel · ext4: handle wraparound when searching for blocks for indirect mapped blocks
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical · fixed in f89bba144938921a2249237ad04a0183ff3f8930 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers can reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in f89bba144938921a2249237ad04a0183ff3f8930, bb81702370fad22c06ca12b6e1648754dbc37e0f, 83170a05908b6cf2fb3235d3065bf613ff866f3c +9
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 5 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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AI-suggested
A fix is available and has been applied in Linux kernel versions 5.16, 6.1.168, 6.6.134, 6.12.80, 6.18.21, and 6.19.11, among others. Users and administrators should upgrade to these or later kernel versions to remediate this vulnerability. No alternative mitigations are indicated by the vendor advisory.
Description
CVE-2026-43067 is a critical vulnerability in the Linux kernel's ext4 filesystem handling. It involves improper handling of block number wraparound when searching for blocks for indirect mapped files, potentially allowing allocation of blocks beyond the 32-bit limit. This issue arises in filesystems mixing extent-mapped and indirect-block mapped files. The vulnerability has been fixed by adding a safety clamp in the ext4_mb_scan_groups() function. The flaw affects multiple Linux kernel versions prior to their respective fixed releases.
References
- git.kernel.org/stable/c/f89bba144938921a2249237ad04a0183ff3f8930 (opens in a new tab)
- git.kernel.org/stable/c/83170a05908b6cf2fb3235d3065bf613ff866f3c (opens in a new tab)
- git.kernel.org/stable/c/4bec4a498ce86314d470ae6144120461f2138c29 (opens in a new tab)
- git.kernel.org/stable/c/12624c5b724a81e14e532972b40d863b0de3b7d1 (opens in a new tab)
- git.kernel.org/stable/c/2a368ccddfc492a0aa951e2caef2985f20e96503 (opens in a new tab)
- git.kernel.org/stable/c/bb81702370fad22c06ca12b6e1648754dbc37e0f (opens in a new tab)