CVE intelligence

CVE-2026-90260

Vulnerability intelligence

Published Sep 17, 2026Sources checked Oct 21, 2026

7.1HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-90260 and is rated High severity with a CVSS score of 7.1. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

CISA KEVNot listedBased on the latest collected catalog

EPSS0.2%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-90260?

In the Linux kernel, the following vulnerability has been resolved:

btrfs: zoned: don't clobber the extent buffer when zeroing it out

On a zoned filesystem a freed-but-still-dirty tree block is written out as zeros (EXTENT_BUFFER_ZONED_ZEROOUT) only to keep the zone write pointer advancing. btree_csum_one_bio() implemented this by memzeroing the extent buffer's own folios before submission.

That destroys the in-memory buffer while it may still be referenced. In particular btrfs_free_tree_block() can run on it afterwards and reads the header to add a delayed reference; once the header has been zeroed it frees bytenr 0 and corrupts the extent tree (the btrfs_header_bytenr(buf) != 0 ASSERT in btrfs_free_tree_block(), or an "unable to find ref" abort).

It is flaky and reproduces under fsstress, e.g. generic/461 and generic/013.

Write the zeros to disk from the shared zero page instead and leave the extent buffer content untouched, so any later reference - including the delayed reference from btrfs_free_tree_block() - still sees a valid header. end_bbio_meta_write() now clears writeback on the buffer's own folios, as the bio no longer carries them.

Source: NVD