CVE-2026-80631

Kernel crash via unchecked btrfs LZO segment length

Published Aug 28, 2026 · Updated Aug 28, 2026

Out-of-bounds access in Linux 5.15 allows attackers to crash the kernel via a crafted LZO-compressed btrfs extent. The lzo_decompress_bio() path checks seg_len against the workspace buffer but not compressed_len, so copy_compressed_segment() advances beyond the bio and dereferences a NULL folio. Triggering requires a malformed on-disk btrfs LZO segment to be read; the resulting kernel fault interrupts the affected system.

CVSS severityUnavailable
Unscored
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in Linux 5.15 allows attackers to crash the kernel via a crafted LZO-compressed btrfs extent. The lzo_decompress_bio() path checks seg_len against the workspace buffer but not compressed_len, so copy_compressed_segment() advances beyond the bio and dereferences a NULL folio. Triggering requires a malformed on-disk btrfs LZO segment to be read; the resulting kernel fault interrupts the affected system.

The record

CVE
CVE-2026-80631
Published
Aug 28, 2026
Updated
Aug 28, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Aug 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.15
  2. Affected versionversion=a6e66e6f8c1b685e11b778bef614480a9c1a5278 <1641d058adfbd50cf95d54581ed5d142ee82c07f
  3. Affected versionversion=a6e66e6f8c1b685e11b778bef614480a9c1a5278 <b0d27d43791b7a3057c3c4aedf9b4aa033d37c46

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.15; version=a6e66e6f8c1b685e11b778bef614480a9c1a5278 <1641d058adfbd50cf95d54581ed5d142ee82c07f; version=a6e66e6f8c1b685e11b778bef614480a9c1a5278 <b0d27d43791b7a3057c3c4aedf9b4aa033d37c46

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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