CVE-2026-80638

Kernel panic via misbounded refcount-record clearing

Published Aug 28, 2026 · Updated Aug 28, 2026

Out-of-bounds write in Linux 6.19 allows local users to trigger a kernel panic by unlinking a refcounted file on OCFS2. In ocfs2_remove_refcount_extent(), a bulk memset uses rf_records after its count field has been aliased to a zero tree-depth value, so the write exceeds the member's 16-byte bound. The path requires a refcounted OCFS2 file whose final leaf block is removed; successful triggering interrupts the host through the fortify panic.

CVSS severityUnavailable
Unscored
EPSS probability0.35%
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 write in Linux 6.19 allows local users to trigger a kernel panic by unlinking a refcounted file on OCFS2. In ocfs2_remove_refcount_extent(), a bulk memset uses rf_records after its count field has been aliased to a zero tree-depth value, so the write exceeds the member's 16-byte bound. The path requires a refcounted OCFS2 file whose final leaf block is removed; successful triggering interrupts the host through the fortify panic.

The record

CVE
CVE-2026-80638
Published
Aug 28, 2026
Updated
Aug 28, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
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=2f26f58df041bbcf692730ff4d8ab0f250d9670d <1ec3cca2d8b6b9ff6584ca626d4c8918bbf48d44
  2. Affected versionversion=2f26f58df041bbcf692730ff4d8ab0f250d9670d <f5255516ec7add3a6d5d37853ad5a9a9ddb14305
  3. Affected versionversion=6.19

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=2f26f58df041bbcf692730ff4d8ab0f250d9670d <1ec3cca2d8b6b9ff6584ca626d4c8918bbf48d44; version=2f26f58df041bbcf692730ff4d8ab0f250d9670d <f5255516ec7add3a6d5d37853ad5a9a9ddb14305; version=6.19

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

T1499Endpoint Denial of Service

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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