SB20261007121 - Use-after-free in Linux kernel btrfs
Published: October 7, 2026
Security Bulletin ID
SB20261007121
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Information disclosure
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Use-after-free (CVE-ID: CVE-2026-98245)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 0 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a local user to trigger access to freed memory in the Linux kernel.
The vulnerability exists due to use-after-free in mark_block_group_to_copy() when iterating over the Btrfs commit root without locking. A local user can trigger iteration concurrently with a transaction commit that swaps and frees the commit root to trigger access to freed memory through extent buffers.
Remediation
Install update from vendor's website.