High 7.5Published Aug 28, 2026

CVE-2026-80631btrfs: lzo: reject compressed segment that overflows the compressed input

Updated under an hour ago (2026-10-19 08:23 UTC)

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Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Received
Record last updated: Oct 15, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from a6e66e6f8c1b685e11b778bef614480a9c1a5278 before be7fb59512ffc2da5d98214a00117dfe9eccab78; from a6e66e6f8c1b685e11b778bef614480a9c1a5278 before 1641d058adfbd50cf95d54581ed5d142ee82c07f; from a6e66e6f8c1b685e11b778bef614480a9c1a5278 before b0d27d43791b7a3057c3c4aedf9b4aa033d37c46	CNA record

References

https://git.kernel.org/stable/c/be7fb59512ffc2da5d98214a00117dfe9eccab78
https://git.kernel.org/stable/c/1641d058adfbd50cf95d54581ed5d142ee82c07f
https://git.kernel.org/stable/c/b0d27d43791b7a3057c3c4aedf9b4aa033d37c46

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.