SB20260816140 - NULL pointer dereference in Linux kernel btrfs

Description

This security bulletin contains information about 1 vulnerability.

1) NULL pointer dereference (CVE-ID: CVE-2026-74571)

CWE-ID: CWE-476 - NULL Pointer Dereference

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a null pointer dereference in btrfs_update_global_block_rsv() when mounting a btrfs filesystem with rescue=ibadroots and corrupted tree roots. A local user can mount a crafted corrupted filesystem image to cause a denial of service.

The issue occurs on fully read-only rescue mounts when the block group tree root or raid stripe tree root cannot be read, leaving the corresponding root pointer NULL while the on-disk feature bit remains set.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/076349e4c8d11f6b58c4549976a513b2b4dc6df2
• https://git.kernel.org/stable/c/51a0e8399858621442807a26057bcd1cd3ced046