CVE-2026-64567

Kernel crash via unchecked free-space-cache counts

Published Aug 5, 2026 · Updated Aug 5, 2026

Out-of-bounds read in Linux btrfs allows local users to crash the kernel by mounting a crafted v1 free-space-cache image. io_ctl_check_crc trusts header-supplied entry and bitmap counts and advances io_ctl->index beyond the pages array allocated from the cache inode size. The trigger requires local access sufficient to mount a checksum-corrected btrfs image; the documented result is a general-protection fault and kernel crash.

CVSS severity7.8
High
EPSS probability0.12%
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 read in Linux btrfs allows local users to crash the kernel by mounting a crafted v1 free-space-cache image. io_ctl_check_crc trusts header-supplied entry and bitmap counts and advances io_ctl->index beyond the pages array allocated from the cache inode size. The trigger requires local access sufficient to mount a checksum-corrected btrfs image; the documented result is a general-protection fault and kernel crash.

The record

CVE
CVE-2026-64567
Published
Aug 5, 2026
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-125
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=3.2
  2. Affected versionversion=5b0e95bf607ddd59b39f52d3d55e6581c817b530 <33878ba25e2638bc0c61623d7a05c9ca2b74c039
  3. Affected versionversion=5b0e95bf607ddd59b39f52d3d55e6581c817b530 <404a0b986e0b6e79738fdf1f0ebbbc43b9acd2a2
  4. Affected versionversion=5b0e95bf607ddd59b39f52d3d55e6581c817b530 <5e1b2ca6b34939e70fb0785e8222b53cf060016f
  5. Affected versionversion=5b0e95bf607ddd59b39f52d3d55e6581c817b530 <a2d8d5647ed854e38f941741aea45b9eb15a6350
  6. Affected versionversion=5b0e95bf607ddd59b39f52d3d55e6581c817b530 <f9fef131fa3f59b857217f522fa5ea430d1b707c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.2; version=5b0e95bf607ddd59b39f52d3d55e6581c817b530 <33878ba25e2638bc0c61623d7a05c9ca2b74c039; version=5b0e95bf607ddd59b39f52d3d55e6581c817b530 <404a0b986e0b6e79738fdf1f0ebbbc43b9acd2a2; version=5b0e95bf607ddd59b39f52d3d55e6581c817b530 <5e1b2ca6b34939e70fb0785e8222b53cf060016f; version=5b0e95bf607ddd59b39f52d3d55e6581c817b530 <a2d8d5647ed854e38f941741aea45b9eb15a6350; version=5b0e95bf607ddd59b39f52d3d55e6581c817b530 <f9fef131fa3f59b857217f522fa5ea430d1b707c

Published CVSS scores

7.8Linux kernel CVE teamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read

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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