VulnerabilityPublished 5 May 2026Updated 6 Nov 2026

CVE-2026-43065: Linux kernel · ext4: always drain queued discard work in ext4_mb_release()

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in e96c2354b170aaa53300c8e8fd59e41b133160f7 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 16:18 UTC

Severity

Low

Rated Low by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in e96c2354b170aaa53300c8e8fd59e41b133160f7, c360e9d0def4f4ae03254a67c683103908555b75, b4737e26d4688b8aea88ad6ea4dbfeb6e78b0327 +4

Exploitation evidence

Disclosed: evidence found.
CVE published 5 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 55cdd0af2bc5ffc92a2deb745627755aecd5db33, < e96c2354b170aaa53300c8e8fd59e41b133160f7	Fixed in e96c2354b170aaa53300c8e8fd59e41b133160f7
LinuxLinux	Affected ≥ 55cdd0af2bc5ffc92a2deb745627755aecd5db33, < c360e9d0def4f4ae03254a67c683103908555b75	Fixed in c360e9d0def4f4ae03254a67c683103908555b75
LinuxLinux	Affected ≥ 55cdd0af2bc5ffc92a2deb745627755aecd5db33, < b4737e26d4688b8aea88ad6ea4dbfeb6e78b0327	Fixed in b4737e26d4688b8aea88ad6ea4dbfeb6e78b0327
LinuxLinux	Affected ≥ 55cdd0af2bc5ffc92a2deb745627755aecd5db33, < 812b6a7cd3e7f3a3e8a24db85bc6313c26cb1098	Fixed in 812b6a7cd3e7f3a3e8a24db85bc6313c26cb1098
LinuxLinux	Affected ≥ 55cdd0af2bc5ffc92a2deb745627755aecd5db33, < 9ee29d20aab228adfb02ca93f87fb53c56c2f3af	Fixed in 9ee29d20aab228adfb02ca93f87fb53c56c2f3af
LinuxLinux	Affected ≥ 55cdd0af2bc5ffc92a2deb745627755aecd5db33, < 9b4d9dda6a71ad3425c8109d27c4c6bfb9da97b8	Fixed in 9b4d9dda6a71ad3425c8109d27c4c6bfb9da97b8

AI-suggested

A fix is available in the Linux kernel as indicated by multiple fixed commit versions. Users should update to a kernel version that includes these fixes to resolve the issue. No additional mitigation steps are required as the patch addresses the problem directly.

Description

CVE-2026-43065 is a vulnerability in the Linux kernel's ext4 filesystem code where queued discard work is not properly drained when remounting the filesystem from discard to nodiscard mode. This can lead to pending discard operations remaining unflushed if the filesystem is unmounted immediately after remounting. The issue was fixed in specific Linux kernel commits.

Impact

The impact is limited to the potential for queued discard work to remain unflushed during a specific remount and unmount sequence. There is no indication of data corruption, privilege escalation, or remote exploitation. The issue is primarily a correctness bug in ext4 discard handling that could affect filesystem behavior under rare conditions.

Summary

The vulnerability involves the ext4 filesystem's handling of discard operations. When the filesystem is initially mounted with the discard option, deleting files queues discard work. If the filesystem is then remounted with the nodiscard option, the discard flag is cleared but the pending discard work is neither cancelled nor flushed. This can cause queued discard work to remain unprocessed if the filesystem is unmounted immediately after remounting. The flaw was identified during patch review and fixed to prevent the issue and avoid false positives in the Sashiko analysis tool. Exploitation requires a specific sequence of mounting with discard, deleting many files, remounting with nodiscard, and unmounting quickly, making deliberate exploitation difficult.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Nov 2026, 16:18 UTC

Technical details

References

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