VulnerabilityPublished 27 May 2026Updated 6 Nov 2026

CVE-2026-45892: Linux kernel · ext4: drop extent cache after doing PARTIAL_VALID1 zeroout

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in f0931a5c17005a0c4fc35bd1a001245effc3354b : update Linux kernel when convenient.

Data as of 6 Nov 2026, 16:05 UTC

Severity

Medium

Rated Medium 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 f0931a5c17005a0c4fc35bd1a001245effc3354b, d8ee559fccdef713f058cfe5f2c03dc9b18be3b1, c2ee51d684adca7645e4aa74adca13f6750390bc +4

Exploitation evidence

Disclosed: evidence found.
CVE published 27 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 ≥ 58ddae5d77b1db3a27b891c75a8fa120239ac092, < f0931a5c17005a0c4fc35bd1a001245effc3354b	Fixed in f0931a5c17005a0c4fc35bd1a001245effc3354b
LinuxLinux	Affected ≥ d17857b4fb9ba5745b59be0ef38fd532991fccbf, < d8ee559fccdef713f058cfe5f2c03dc9b18be3b1	Fixed in d8ee559fccdef713f058cfe5f2c03dc9b18be3b1
LinuxLinux	Affected ≥ d67c8ecf3d8fda9b8ef80e6f665d84b6d6ac9d88, < c2ee51d684adca7645e4aa74adca13f6750390bc	Fixed in c2ee51d684adca7645e4aa74adca13f6750390bc
LinuxLinux	Affected ≥ 7015fcf473796e1d2d876f241bd9e0c36f3d4eef, < a1b962a821e7a52d48212ae269b45808b4411267	Fixed in a1b962a821e7a52d48212ae269b45808b4411267
LinuxLinux	Affected ≥ ddf854e59166533b0f46ba32cd6cd9aca3197d1b, < 28db4bfc6f82fd20e2aadb7fc162244109a4eb31	Fixed in 28db4bfc6f82fd20e2aadb7fc162244109a4eb31
LinuxLinux	Affected ≥ 1bf6974822d1dba86cf11b5f05498581cf3488a2, < 6d882ea3b0931b43530d44149b79fcd4ffc13030	Fixed in 6d882ea3b0931b43530d44149b79fcd4ffc13030

AI-suggested

A fix for this vulnerability is available in Linux kernel version 6.1.168. Users and administrators should upgrade to version 6.1.168 or later to remediate this issue. No additional mitigation steps are indicated by the vendor advisory.

Description

CVE-2026-45892 is a vulnerability in the Linux kernel's ext4 filesystem related to improper handling of extent cache after partial zeroing of unwritten extents. The flaw occurs when splitting an unwritten extent and converting it to initialized, which can leave stale unwritten extents in the extent status tree. This inconsistency could affect filesystem integrity. The issue is fixed in Linux kernel version 6.1.168.

Impact

This flaw can lead to stale unwritten extents remaining in the extent status tree, potentially causing filesystem inconsistencies or corruption during file operations involving buffered writes to unwritten extents. The vulnerability affects the integrity of the ext4 filesystem's extent tracking but there is no indication of remote exploitability or privilege escalation from the provided data.

Summary

The vulnerability involves ext4_split_extent() in the Linux kernel ext4 filesystem code, where splitting an unwritten extent with EXT4_EXT_MAY_ZEROOUT and EXT4_EXT_DATA_VALID2 flags set can fail to properly update the extent status tree. Specifically, after a partial zeroout operation, stale unwritten extents may remain cached, causing inconsistency between on-disk extents and the extent status tree. The fix ensures the extent status entry is always cached after zeroing out the second part, preventing stale entries.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Nov 2026, 16:05 UTC

Technical details

References

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