CVE-2026-80631
Received
Received - Intake
Buffer Overflow in Linux Kernel Btrfs LZO Compression
Vulnerability report for CVE-2026-80631, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-08-28
Last updated on: 2026-08-28
Assigner: kernel.org
Description
Description
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 Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | kernel | * |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
