Linux: Use After Free
CVE-2025-38437 is a high-severity use after free 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 e38ec88a2b42c494601b1213816d75f0b54d9bf0, 97c355989928a5f60b228ef5266c1be67a46cdf9, 815f1161d6dbc4c54ccf94b7d3fdeab34b4d7477 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 0.45% 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 e38ec88a2b42c494601b1213816d75f0b54d9bf0 or 97c355989928a5f60b228ef5266c1be67a46cdf9 or 815f1161d6dbc4c54ccf94b7d3fdeab34b4d7477 or 8106adc21a2270c16abf69cd74ccd7c79c6e7acd, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.146 or 6.6.99 or 6.12.39 or 6.15.7, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 0626e6641f6b467447c81dd7678a69c66f7746cf up to, but not including, e38ec88a2b42c494601b1213816d75f0b54d9bf0; 0626e6641f6b467447c81dd7678a69c66f7746cf up to, but not including, 97c355989928a5f60b228ef5266c1be67a46cdf9; 0626e6641f6b467447c81dd7678a69c66f7746cf up to, but not including, 815f1161d6dbc4c54ccf94b7d3fdeab34b4d7477; 0626e6641f6b467447c81dd7678a69c66f7746cf up to, but not including, 8106adc21a2270c16abf69cd74ccd7c79c6e7acd; 0626e6641f6b467447c81dd7678a69c66f7746cf up to, but not including, 50f930db22365738d9387c974416f38a06e8057e; 5.15 | e38ec88a2b42c494601b1213816d75f0b54d9bf0, 97c355989928a5f60b228ef5266c1be67a46cdf9, 815f1161d6dbc4c54ccf94b7d3fdeab34b4d7477, 8106adc21a2270c16abf69cd74ccd7c79c6e7acd, 50f930db22365738d9387c974416f38a06e8057e |
| Linux | Linux Kernel | 5.15 up to, but not including, 6.1.146; 6.2 up to, but not including, 6.6.99; 6.7 up to, but not including, 6.12.39; 6.13 up to, but not including, 6.15.7; 6.16 | 6.1.146, 6.6.99, 6.12.39, 6.15.7 |
| 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 | 8.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix potential use-after-free in oplock/lease break ack If ksmbd_iov_pin_rsp return error, use-after-free can happen by accessing opinfo->state and opinfo_put and ksmbd_fd_put could called twice.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/50f930db22365738d9387c974416f38a06e8057e
- git.kernel.org/stable/c/8106adc21a2270c16abf69cd74ccd7c79c6e7acd
- git.kernel.org/stable/c/815f1161d6dbc4c54ccf94b7d3fdeab34b4d7477
- git.kernel.org/stable/c/97c355989928a5f60b228ef5266c1be67a46cdf9
- git.kernel.org/stable/c/e38ec88a2b42c494601b1213816d75f0b54d9bf0
Third-party and government advisories
- lists.debian.org/debian-lts-announce/2025/10/msg00008.htmlThird Party Advisory
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 9.8 Critical severity
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