CVE-2026-80537Hinoki check available

Kernel compromise via XFS root-level off-by-one

Published Aug 26, 2026 · Updated Aug 27, 2026

Out-of-bounds write in Linux kernel XFS allows local users to crash or compromise the kernel by mounting a crafted rtreflink image. xfs_rtrefcountbt_verify() and xfs_iformat_rtrefcount() accept a root level equal to the computed maximum, so cursor setup adds one and the first btree operation writes beyond bc_levels. Reachability requires an rtreflink image with metadir, realtime, and reflink metadata, followed by mount recovery or FS_IOC_GETFSMAP; the write can panic or compromise the host kernel.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Out-of-bounds write in Linux kernel XFS allows local users to crash or compromise the kernel by mounting a crafted rtreflink image. xfs_rtrefcountbt_verify() and xfs_iformat_rtrefcount() accept a root level equal to the computed maximum, so cursor setup adds one and the first btree operation writes beyond bc_levels. Reachability requires an rtreflink image with metadir, realtime, and reflink metadata, followed by mount recovery or FS_IOC_GETFSMAP; the write can panic or compromise the host kernel.

The record

CVE
CVE-2026-80537
Published
Aug 26, 2026
Updated
Aug 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 27, 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=6.14
  2. Affected versionversion=9abe03a0e4f978615a2b1b484b8d09ca84c16ea0 <8a0ecae2ecda9f9a83a496ed05c42c4b1f5c3f2d
  3. Affected versionversion=9abe03a0e4f978615a2b1b484b8d09ca84c16ea0 <cc3144da377de5fb422d44a2311f978623f7c900
  4. Affected versionversion=9abe03a0e4f978615a2b1b484b8d09ca84c16ea0 <ccebfc309441e0b37b2e6ece90f18810a489d326

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.14; version=9abe03a0e4f978615a2b1b484b8d09ca84c16ea0 <8a0ecae2ecda9f9a83a496ed05c42c4b1f5c3f2d; version=9abe03a0e4f978615a2b1b484b8d09ca84c16ea0 <cc3144da377de5fb422d44a2311f978623f7c900; version=9abe03a0e4f978615a2b1b484b8d09ca84c16ea0 <ccebfc309441e0b37b2e6ece90f18810a489d326

Published CVSS scores

6.1Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H
7.8Linux kernel CVE teamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

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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