CVE-2025-68359Network attack vector

Kernel memory corruption via btrfs qgroup double free

Published Dec 24, 2025 · Updated Dec 24, 2025

A double free in Linux btrfs qgroup handling allows remote attackers to corrupt kernel memory through writable NFS or ksmbd shares. When add_delayed_ref_head() fails after btrfs_qgroup_trace_extent_nolock() finds an existing record, caller and callee both free the same qrecord. Reachability requires qgroup accounting and an anonymous writable NFS export or writable ksmbd guest share; resulting freelist corruption enables kernel reads, writes, control-flow hijacking, or a panic.

CVSS severity9.8
Critical
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A double free in Linux btrfs qgroup handling allows remote attackers to corrupt kernel memory through writable NFS or ksmbd shares. When add_delayed_ref_head() fails after btrfs_qgroup_trace_extent_nolock() finds an existing record, caller and callee both free the same qrecord. Reachability requires qgroup accounting and an anonymous writable NFS export or writable ksmbd guest share; resulting freelist corruption enables kernel reads, writes, control-flow hijacking, or a panic.

The record

CVE
CVE-2025-68359
Published
Dec 24, 2025
Updated
Dec 24, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 24, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 24, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=6.12
  2. Affected versionversion=6ef8fbce010421bf742b12b8f8f2b2d2ff154845 <364685c4c2d9c9f4408d95451bcf42fdeebc3ebb
  3. Affected versionversion=6ef8fbce010421bf742b12b8f8f2b2d2ff154845 <725e46298876a2cc1f1c3fb22ba69d29102c3ddf
  4. Affected versionversion=6ef8fbce010421bf742b12b8f8f2b2d2ff154845 <7617680769e3119dfb3b43a2b7c287ce2242211c

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.12; version=6ef8fbce010421bf742b12b8f8f2b2d2ff154845 <364685c4c2d9c9f4408d95451bcf42fdeebc3ebb; version=6ef8fbce010421bf742b12b8f8f2b2d2ff154845 <725e46298876a2cc1f1c3fb22ba69d29102c3ddf; version=6ef8fbce010421bf742b12b8f8f2b2d2ff154845 <7617680769e3119dfb3b43a2b7c287ce2242211c

Published CVSS scores

9.8LinuxCVSS:3.1/AV:N/AC:L/PR:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1190Exploit Public-Facing Application

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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