CVE-2024-56581

Local privilege escalation via stale Btrfs reference

Published Dec 27, 2024 · Updated Aug 5, 2026

Use-after-free in Linux kernel Btrfs ref verification allows local users to gain elevated privileges through filesystem operations. btrfs_ref_tree_mod() frees a newly inserted reference after an invalid delayed-reference action without first removing it from the block entry's red-black tree, leaving btrfs_free_ref_cache() to dereference stale memory. Reachability requires local low-privileged access and a Btrfs workload that drives the unexpected action; the stale pointer can corrupt kernel memory or crash the host.

CVSS severity7.8
High
EPSS probability0.24%
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 Linux kernel Btrfs ref verification allows local users to gain elevated privileges through filesystem operations. btrfs_ref_tree_mod() frees a newly inserted reference after an invalid delayed-reference action without first removing it from the block entry's red-black tree, leaving btrfs_free_ref_cache() to dereference stale memory. Reachability requires local low-privileged access and a Btrfs workload that drives the unexpected action; the stale pointer can corrupt kernel memory or crash the host.

The record

CVE
CVE-2024-56581
Published
Dec 27, 2024
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. Dec 27, 2024CVE 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

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=4.15
  2. Affected versionversion=fd708b81d972a0714b02a60eb4792fdbf15868c4 <4275ac2741941c9c7c2293619fdbacb9f70ba85b
  3. Affected versionversion=fd708b81d972a0714b02a60eb4792fdbf15868c4 <6370db28af9a8ae3bbdfe97f8a48f8f995e144cf
  4. Affected versionversion=fd708b81d972a0714b02a60eb4792fdbf15868c4 <6fd018aa168e472ce35be32296d109db6adb87ea
  5. Affected versionversion=fd708b81d972a0714b02a60eb4792fdbf15868c4 <7c4e39f9d2af4abaf82ca0e315d1fd340456620f
  6. Affected versionversion=fd708b81d972a0714b02a60eb4792fdbf15868c4 <a6f9e7a0bf1185c9070c0de03bb85eafb9abd650
  7. Affected versionversion=fd708b81d972a0714b02a60eb4792fdbf15868c4 <d2b85ce0561fde894e28fa01bd5d32820d585006
  8. Affected versionversion=fd708b81d972a0714b02a60eb4792fdbf15868c4 <dfb9fe7de61f34cc241ab3900bdde93341096e0e

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.15; version=fd708b81d972a0714b02a60eb4792fdbf15868c4 <4275ac2741941c9c7c2293619fdbacb9f70ba85b; version=fd708b81d972a0714b02a60eb4792fdbf15868c4 <6370db28af9a8ae3bbdfe97f8a48f8f995e144cf; version=fd708b81d972a0714b02a60eb4792fdbf15868c4 <6fd018aa168e472ce35be32296d109db6adb87ea; version=fd708b81d972a0714b02a60eb4792fdbf15868c4 <7c4e39f9d2af4abaf82ca0e315d1fd340456620f; version=fd708b81d972a0714b02a60eb4792fdbf15868c4 <a6f9e7a0bf1185c9070c0de03bb85eafb9abd650; version=fd708b81d972a0714b02a60eb4792fdbf15868c4 <d2b85ce0561fde894e28fa01bd5d32820d585006; version=fd708b81d972a0714b02a60eb4792fdbf15868c4 <dfb9fe7de61f34cc241ab3900bdde93341096e0e

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 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

CWE-416Use After Free
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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