CVE intelligence

CVE-2026-89644

Vulnerability intelligence

Published Sep 11, 2026Sources checked Nov 3, 2026

N/ACVSS not listedScore unavailable

What this means

Review the available evidence

CVE-2026-89644. 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-2026-89644?

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

btrfs: fix extent map leak in NOCOW direct I/O write

btrfs_dio_iomap_begin() calls btrfs_get_extent(), which returns an extent map reference that must be dropped on all exit paths.

For direct writes into a NOCOW range, btrfs_get_blocks_direct_write() keeps using that extent map and asks btrfs_create_dio_extent() to allocate the ordered extent. If that fails, for example because btrfs_alloc_ordered_extent() fails, the function returns the error without dropping the input extent map.

The PREALLOC path avoided this by dropping the input extent map before replacing it with the newly created one.

Check the error from btrfs_create_dio_extent() before replacing the map and drop the input extent map on failure.

Source: NVD