Linux Kernel Btrfs filesystem Vulnerability Rated 7.5 CVSS

Status: UPDATED  |  Advisory ID: CVE-2026-80631

Key Details

Affected Products, Subsystems & Sectors

What to Know

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

btrfs: lzo: reject compressed segment that overflows the compressed input

lzo_decompress_bio() validates each on-disk segment length seg_len only

against the workspace cbuf size, not against the compressed input size

(compressed_len, the total folio bytes of the bio). A crafted extent can

carry a segment whose seg_len passes the cbuf check but runs past the end

of the bio, so copy_compressed_segment() walks off the last folio:

get_current_folio() then returns the NULL folio from bio_next_folio(), and

with CONFIG_BTRFS_ASSERT disabled (default) folio_size(NULL) faults.

BUG: KASAN: null-ptr-deref in lzo_decompress_bio (fs/btrfs/lzo.c:383)

Read of size 8 at addr 0000000000000000 by task kworker/u8:1/29

Workqueue: btrfs-endio simple_end_io_work

kasan_report (mm/kasan/report.c:590)

lzo_decompress_bio (fs/btrfs/lzo.c:383)

end_bbio_compressed_read (fs/btrfs/compression.c:1065)

btrfs_bio_end_io (fs/btrfs/bio.c:135)

btrfs_check_read_bio (fs/btrfs/bio.c:180 fs/btrfs/bio.c:285)

simple_end_io_work

process_one_work

worker_thread

Reject any segment whose payload would extend beyond compressed_len before

copying it, treating it as corruption like the other on-disk validation

failures in this function. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References