CVE-2024-56759

Kernel memory corruption via stale Btrfs extent buffer

Published Jan 6, 2025 · Updated Aug 5, 2026

Use-after-free in the Btrfs copy-on-write path in Linux allows local users to disclose or corrupt kernel memory through filesystem writes. When btrfs_force_cow_block drops the last extent-buffer reference, preemption can release the buffer before trace_btrfs_cow_block dereferences it. Reachability requires CONFIG_PREEMPT, the Btrfs COW tracepoint to be enabled, and attacker-writable storage on Btrfs; the stale dereference can leak memory or crash the kernel.

CVSS severity7.8
High
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Btrfs copy-on-write path in Linux allows local users to disclose or corrupt kernel memory through filesystem writes. When btrfs_force_cow_block drops the last extent-buffer reference, preemption can release the buffer before trace_btrfs_cow_block dereferences it. Reachability requires CONFIG_PREEMPT, the Btrfs COW tracepoint to be enabled, and attacker-writable storage on Btrfs; the stale dereference can leak memory or crash the kernel.

The record

CVE
CVE-2024-56759
Published
Jan 6, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 6, 2025CVE 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=3083ee2e18b701122a3b841db83448543a87a583 <44f52bbe96dfdbe4aca3818a2534520082a07040
  2. Affected versionversion=3083ee2e18b701122a3b841db83448543a87a583 <526ff5b27f090fb15040471f892cd2c9899ce314
  3. Affected versionversion=3083ee2e18b701122a3b841db83448543a87a583 <66376f1a73cba57fd0af2631d7888605b738e499
  4. Affected versionversion=3083ee2e18b701122a3b841db83448543a87a583 <9a466b8693b9add05de99af00c7bdff8259ecf19
  5. Affected versionversion=3083ee2e18b701122a3b841db83448543a87a583 <ba5120a2fb5f23b4d39d302e181aa5d4e28a90d1
  6. Affected versionversion=3083ee2e18b701122a3b841db83448543a87a583 <c3a403d8ce36f5a809a492581de5ad17843e4701
  7. Affected versionversion=3.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3083ee2e18b701122a3b841db83448543a87a583 <44f52bbe96dfdbe4aca3818a2534520082a07040; version=3083ee2e18b701122a3b841db83448543a87a583 <526ff5b27f090fb15040471f892cd2c9899ce314; version=3083ee2e18b701122a3b841db83448543a87a583 <66376f1a73cba57fd0af2631d7888605b738e499; version=3083ee2e18b701122a3b841db83448543a87a583 <9a466b8693b9add05de99af00c7bdff8259ecf19; version=3083ee2e18b701122a3b841db83448543a87a583 <ba5120a2fb5f23b4d39d302e181aa5d4e28a90d1; version=3083ee2e18b701122a3b841db83448543a87a583 <c3a403d8ce36f5a809a492581de5ad17843e4701; version=3.4

Published CVSS scores

7.8CISA ADPCVSS: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 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-416Use After Free
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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