btrfs: lzo: reject compressed segment that overflows the compressed input
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 6.12.114, 6.18.57, 7.1.5, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
Not affected: 3 products
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-80631
- 2026-10-03 Alias added: GHSA-hqpg-7vj3-59jv
- 2026-10-16 Fix available: Linux/[email protected], Linux/Linux@be7fb59512ffc2da5d98214a00117dfe9eccab78 · CNA
- 2026-10-16 1 new reference · CNA
- 2026-10-21 Fix available: Linux/Linux@1c48c8c807e49ac4f72819a89035fb8d2d094015, Linux/[email protected], Linux/[email protected] +1 · CNA
- 2026-10-21 2 new references · CNA
- 2026-10-30 Fix available: Linux/[email protected], Linux/Linux@e4325fb00e0c7269cb67f97d7148507787a57fd7 · CNA
- 2026-10-30 1 new reference · CNA
References
Other 6
- https://git.kernel.org/stable/c/e4325fb00e0c7269cb67f97d7148507787a57fd7
- https://git.kernel.org/stable/c/d9b17f9ce67d00e48fab62dcae197612a58f625f
- https://git.kernel.org/stable/c/1c48c8c807e49ac4f72819a89035fb8d2d094015
- https://git.kernel.org/stable/c/be7fb59512ffc2da5d98214a00117dfe9eccab78
- https://git.kernel.org/stable/c/1641d058adfbd50cf95d54581ed5d142ee82c07f
- https://git.kernel.org/stable/c/b0d27d43791b7a3057c3c4aedf9b4aa033d37c46
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Sources
- CVE-2026-80631 · CVE Program
- CVE-2026-80631 · NVD
- FIRST EPSS
- GHSA-hqpg-7vj3-59jv · GitHub Advisory Database · CC BY 4.0
- CVE-2026-80631 · Red Hat security data · CC BY 4.0
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