CVE-2024-56758: Linux kernel · btrfs: check folio mapping after unlock in relocate_one_folio()
Source GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 29 Oct 2026, 23:52 UTC
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 6 Jan 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
AI-suggested
A fix for this vulnerability has been implemented in the Linux kernel. Users and administrators should apply the official kernel updates that include this patch to resolve the issue. No additional mitigation steps are indicated or required beyond applying the fix.
Description
CVE-2024-56758 is a medium severity vulnerability in the Linux kernel's Btrfs filesystem code. It involves a race condition in the relocate_one_folio() function where a folio's mapping can be modified by another thread after unlocking but before relocking, leading to a NULL pointer dereference and kernel crash. This occurs particularly during concurrent relocation and transaction abort operations. The issue arises because the code fails to check if the folio's mapping is NULL before calling set_extent_mapping(), which assumes a valid mapping. This flaw can cause system instability and crashes.
References
- nvd.nist.gov/vuln/detail/CVE-2024-56758 (opens in a new tab)
- git.kernel.org/stable/c/36679fab54fa7bcffafd469e2c474c1fc4beaee0 (opens in a new tab)
- git.kernel.org/stable/c/3e74859ee35edc33a022c3f3971df066ea0ca6b9 (opens in a new tab)
- git.kernel.org/stable/c/c7b1bd52a031ad0144d42eef0ba8471ce75122dd (opens in a new tab)
- git.kernel.org/stable/c/d508e56270389b3a16f5b3cf247f4eb1bbad1578 (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/10/msg00008.html (opens in a new tab)