CVE-2026-43066
MediumIn the Linux kernel, the following vulnerability has been resolved: ext4: fix iloc.bh leak in ext4_fc_replay_inode() error paths During code review, Joseph found that ext4_fc_replay_inode() calls ext4_get_fc_inode_loc() to get the inode location, which holds a reference to iloc.bh that must be released via brelse(). However, several error paths jump to the 'out' label without releasing iloc.bh: - ext4_handle_dirty_metadata() failure - sync_dirty_buffer() failure - ext4_mark_inode_used() failure - ext4_iget() failure Fix this by introducing an 'out_brelse' label placed just before the existing 'out' label to ensure iloc.bh is always released. Additionally, make ext4_fc_replay_inode() propagate errors properly instead of always returning 0.
CVSS 3.1 score
5.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness type
CWE-401CVE-2026-43066 is a Memory Leak vulnerability
What is Memory Leak?
The product does not release memory after use, causing gradual resource exhaustion. Learn more on MITRE CWE
Affected versions
Linux kernel versions
5.10
and later are affected. Fixed in
5.10.253,
5.15.203,
6.1.168,
6.6.131,
6.12.80,
6.18.21,
6.19.11,
7.0
and their respective stable series.
References
The following references provide additional information about CVE-2026-43066 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.
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PatchKernel patch commithttps://git.kernel.org/stable/c/0892f12cd49fde5d5db68137923db107f894f3a3
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PatchKernel patch commithttps://git.kernel.org/stable/c/19782b4c793b49a6aa4abbb307ddff3610009d21
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PatchKernel patch commithttps://git.kernel.org/stable/c/5a63033696e60b5d70816f1d119645ac5b0b0a03
Frequently asked questions
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What is CVE-2026-43066?
CVE-2026-43066 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as a Memory Leak flaw (CWE-401) . It affects Linux kernel versions from 5.10 onward and has been patched in 5.10.253, 5.15.203, 6.1.168 and others. CVE-2026-43066 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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What is the CVSS score for CVE-2026-43066?
CVE-2026-43066 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. -
Is there a patch available for CVE-2026-43066?
Yes — CVE-2026-43066 has been patched. Fixed versions include 5.10.253, 5.15.203, 6.1.168 and others. If you are running Linux kernel 5.10 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-43066 actively exploited?
No — CVE-2026-43066 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.
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What is Memory Leak (CWE-401)?
The product does not release memory after use, causing gradual resource exhaustion. View CWE-401 on MITRE CWE →