Linux: Use of Uninitialized Resource
CVE-2025-38579 is a high-severity use of uninitialized resource vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 08e8ab00a6d20d5544c932ee85a297d833895141, e68b751ec2b15d866967812c57cfdfc1eba6a269, dabfa3952c8e6bfe6414dbf32e8b6c5f349dc898 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.19% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 08e8ab00a6d20d5544c932ee85a297d833895141 or e68b751ec2b15d866967812c57cfdfc1eba6a269 or dabfa3952c8e6bfe6414dbf32e8b6c5f349dc898 or 44a79437309e0ee2276ac17aaedc71253af253a8, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.190 or 6.1.148 or 6.6.102 or 6.12.42, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 94afd6d6e5253179c9b891d02081cc8355a11768 up to, but not including, 08e8ab00a6d20d5544c932ee85a297d833895141; 94afd6d6e5253179c9b891d02081cc8355a11768 up to, but not including, e68b751ec2b15d866967812c57cfdfc1eba6a269; 94afd6d6e5253179c9b891d02081cc8355a11768 up to, but not including, dabfa3952c8e6bfe6414dbf32e8b6c5f349dc898; 94afd6d6e5253179c9b891d02081cc8355a11768 up to, but not including, 44a79437309e0ee2276ac17aaedc71253af253a8; 94afd6d6e5253179c9b891d02081cc8355a11768 up to, but not including, cc1615d5aba4f396cf412579928539a2b124c8a0; 94afd6d6e5253179c9b891d02081cc8355a11768 up to, but not including, 01b6f5955e0008af6bc3a181310d2744bb349800; 94afd6d6e5253179c9b891d02081cc8355a11768 up to, but not including, 154467f4ad033473e5c903a03e7b9bca7df9a0fa; 5.15 | 08e8ab00a6d20d5544c932ee85a297d833895141, e68b751ec2b15d866967812c57cfdfc1eba6a269, dabfa3952c8e6bfe6414dbf32e8b6c5f349dc898, 44a79437309e0ee2276ac17aaedc71253af253a8, cc1615d5aba4f396cf412579928539a2b124c8a0, 01b6f5955e0008af6bc3a181310d2744bb349800 |
| Linux | Linux Kernel | 5.15 up to, but not including, 5.15.190; 5.16 up to, but not including, 6.1.148; 6.2 up to, but not including, 6.6.102; 6.7 up to, but not including, 6.12.42; 6.13 up to, but not including, 6.15.10; 6.16 up to, but not including, 6.16.1 | 5.15.190, 6.1.148, 6.6.102, 6.12.42, 6.15.10, 6.16.1 |
| Debian | Debian Linux | 11.0 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix KMSAN uninit-value in extent_info usage KMSAN reported a use of uninitialized value in `__is_extent_mergeable()` and `__is_back_mergeable()` via the read extent tree path. The root cause is that `get_read_extent_info()` only initializes three fields (`fofs`, `blk`, `len`) of `struct extent_info`, leaving the remaining fields uninitialized. This leads to undefined behavior when those fields are accessed later, especially during extent merging. Fix it by zero-initializing the `extent_info` struct before population.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Uninitialized Resource
The product uses or accesses a resource that has not been initialized.
How developers prevent this class of flaw
- Explicitly initialize the resource before use. If this is performed through an API function or standard procedure, follow all required steps.
- Pay close attention to complex conditionals that affect initialization, since some branches might not perform the initialization.
- Avoid race conditions (CWE-362) during initialization routines.
More Use of Uninitialized Resource vulnerabilities (CWE-908)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/01b6f5955e0008af6bc3a181310d2744bb349800
- git.kernel.org/stable/c/08e8ab00a6d20d5544c932ee85a297d833895141
- git.kernel.org/stable/c/154467f4ad033473e5c903a03e7b9bca7df9a0fa
- git.kernel.org/stable/c/44a79437309e0ee2276ac17aaedc71253af253a8
- git.kernel.org/stable/c/cc1615d5aba4f396cf412579928539a2b124c8a0
- git.kernel.org/stable/c/dabfa3952c8e6bfe6414dbf32e8b6c5f349dc898
- git.kernel.org/stable/c/e68b751ec2b15d866967812c57cfdfc1eba6a269
Third-party and government advisories
- lists.debian.org/debian-lts-announce/2025/10/msg00008.htmlMailing List, Third Party Advisory
Recent Use of Uninitialized Resource vulnerabilities
- 7.8 High severity
- 7.1 High severity
- 7.5 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
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