CVE-2025-40243: Linux kernel · hfs: fix KMSAN uninit-value issue in hfs_find_set_zero_bits() The syzbot
Source GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 06:26 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 4 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 2026-10-26.
What to do
AI-suggested
The issue was fixed by replacing kmalloc() with kzalloc() in the Linux kernel source code for the HFS filesystem. Users should apply the official Linux kernel updates once available that include this fix.
Description
A use of uninitialized memory issue was found and fixed in the Linux kernel's HFS filesystem code in the function hfs_find_set_zero_bits(). The problem was caused by the use of kmalloc() which does not zero memory, potentially leading to corrupted bitmap operations and filesystem errors. The fix replaced kmalloc() with kzalloc() to ensure allocated memory is zeroed, preventing uninitialized data from affecting bitmap handling.
References
- nvd.nist.gov/vuln/detail/CVE-2025-40243 (opens in a new tab)
- git.kernel.org/stable/c/2048ec5b98dbdfe0b929d2e42dc7a54c389c53dd (opens in a new tab)
- git.kernel.org/stable/c/2a112cdd66f5a132da5235ca31a320528c86bf33 (opens in a new tab)
- git.kernel.org/stable/c/3b447fd401824e1ccf0b769188edefe866a1e676 (opens in a new tab)
- git.kernel.org/stable/c/502fa92a71f344611101bd04ef1a595b8b6014f5 (opens in a new tab)
- git.kernel.org/stable/c/bf1683078fbdd09a7f7f9b74121ebaa03432bd00 (opens in a new tab)
- git.kernel.org/stable/c/cfafefcb0e1fc60135f7040f4aed0a4aef4f76ca (opens in a new tab)
- git.kernel.org/stable/c/e148ed5cda8fd96d4620c4622fb02f552a2d166a (opens in a new tab)
- git.kernel.org/stable/c/fc56548fca732f3d3692c83b40db796259a03887 (opens in a new tab)