CVE-2026-45892

What it is

In the Linux kernel, the following vulnerability has been resolved: ext4: drop extent cache after doing PARTIAL_VALID1 zeroout When splitting an unwritten extent in the middle and converting it to initialized in ext4_split_extent() with the EXT4_EXT_MAY_ZEROOUT and EXT4_EXT_DATA_VALID2 flags set, it could leave a stale unwritten extent. Assume we have an unwritten file and buffered write in the middle of it without dioread_nolock enabled, it will allocate blocks as written extent. 0 A B N [UUUUUUUUUUUU] on-disk extent U: unwritten extent [UUUUUUUUUUUU] extent status tree [--DDDDDDDD--] D: valid data |<- ->| ----> this range needs to be initialized ext4_split_extent() first try to split this extent at B with EXT4_EXT_DATA_PARTIAL_VALID1 and EXT4_EXT_MAY_ZEROOUT flag set, but ext4_split_extent_at() failed to split this extent due to temporary lack of space. It zeroout B to N and leave the entire extent as unwritten. 0 A B N [UUUUUUUUUUUU] on-disk extent [UUUUUUUUUUUU] extent status tree [--DDDDDDDDZZ] Z: zeroed data ext4_split_extent() then try to split this extent at A with EXT4_EXT_DATA_VALID2 flag set. This time, it split successfully and leave an written extent from A to N. 0 A B N [UUWWWWWWWWWW] on-disk extent W: written extent [UUUUUUUUUUUU] extent status tree [--DDDDDDDDZZ] Finally ext4_map_create_blocks() only insert extent A to B to the extent status tree, and leave an stale unwritten extent in the status tree. 0 A B N [UUWWWWWWWWWW] on-disk extent W: written extent [UUWWWWWWWWUU] extent status tree [--DDDDDDDDZZ] Fix this issue by always cached extent status entry after zeroing out the second part.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-05-27 14:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-25 21:11 UTC Last updatedMost recent change to the record

Details

Published

2026-05-27 14:17 UTC

Last modified

2026-06-25 21:11 UTC

Exploit probability

0.2% · EPSS, next 30 days

Record status

Analyzed

Affected

• Linux Kernel 6.1.167

Attack profile CVSS 3.1 · 5.5

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High