CVE-2025-40244: Linux kernel · hfsplus: fix KMSAN uninit-value issue in __hfsplus_ext_cache_extent()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 6.12.0 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 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.
- Patch
- Available – fixed in 6.12.0
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 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Red Hatredhat/kernelpkg:rpm/redhat/kernelOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix for this vulnerability has been implemented in Linux kernel versions after 6.12.0-rc5. Users and administrators should update to a kernel version that includes this fix to mitigate the issue. Since this is a kernel-level flaw, applying the official kernel patch or upgrading to a fixed kernel release is the recommended remediation. Patch status is not explicitly confirmed in the input data; check the vendor advisory for current remediation guidance.
Description
A high severity vulnerability (CVE-2025-40244) in the Linux kernel's HFS+ filesystem driver was identified and resolved. The issue involved an uninitialized value detected by Kernel Memory Sanitizer (KMSAN) in the __hfsplus_ext_cache_extent() function, which could lead to kernel panic and potentially allow an attacker with local privileges to cause denial of service or escalate privileges. The vulnerability was reported by syzbot and fixed in kernel versions after 6.12.0-rc5. No known exploits are reported in the wild.
References
- nvd.nist.gov/vuln/detail/CVE-2025-40244 (opens in a new tab)
- git.kernel.org/stable/c/14c673a2f3ecf650b694a52a88688f1d71849899 (opens in a new tab)
- git.kernel.org/stable/c/4840ceadef4290c56cc422f0fc697655f3cbf070 (opens in a new tab)
- git.kernel.org/stable/c/99202d94909d323a30d154ab0261c0a07166daec (opens in a new tab)
- git.kernel.org/stable/c/a5bfb13b4f406aef1a450f99d22d3e48df01528c (opens in a new tab)
- git.kernel.org/stable/c/b8a72692aa42b7dcd179a96b90bc2763ac74576a (opens in a new tab)
- git.kernel.org/stable/c/c135b8dca65526aa5b8814e9954e0ae317d9c598 (opens in a new tab)
- git.kernel.org/stable/c/c1ec90bed504640a42bb20a5f413be39cd17ad71 (opens in a new tab)
- git.kernel.org/stable/c/d7e313039a8f3a6ee072dc5ff4643234d2d735cf (opens in a new tab)