Linux: Use After Free
CVE-2025-38656 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 5c432da1ee191e9f7830dd516456706063d7bec3, f95598a133a905fd937354ad902773d05593b8b9, 991e2066f6009d3cb898413058c62dbcc92bd6d2 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 0.22% 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 5c432da1ee191e9f7830dd516456706063d7bec3 or f95598a133a905fd937354ad902773d05593b8b9 or 991e2066f6009d3cb898413058c62dbcc92bd6d2 or 1d068272c21d886d06526454b68368100ba0a720, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.5 or 5.11 or 5.16 or 6.2, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | ca980f1911a7144d451d1c31298ab8507c6bd88f up to, but not including, 5c432da1ee191e9f7830dd516456706063d7bec3; 7dd6350307af6521b6240b295c93b7eec4daebe6 up to, but not including, f95598a133a905fd937354ad902773d05593b8b9; c0e43c3f6c0a79381b468574c241065998412b7c up to, but not including, 991e2066f6009d3cb898413058c62dbcc92bd6d2; 70a1b527eaea9430b1bd87de59f3b9f6bd225701 up to, but not including, 1d068272c21d886d06526454b68368100ba0a720; 90a0d9f339960448a3acc1437a46730f975efd6a up to, but not including, cf80c02a9fdb6c5bc8508beb6a0f6a1294fc32f6; c80832d445653baba5ac80cd2c2637c437ac881b; b398120fbe0acfef60b16f6a0f69902d385d7728; 2e9f85ee3b46453a2f250a57d3a9f10c70c71202; and 7 more ranges | 5c432da1ee191e9f7830dd516456706063d7bec3, f95598a133a905fd937354ad902773d05593b8b9, 991e2066f6009d3cb898413058c62dbcc92bd6d2, 1d068272c21d886d06526454b68368100ba0a720, cf80c02a9fdb6c5bc8508beb6a0f6a1294fc32f6, 5.5 |
| Linux | Linux Kernel | 5.4.297 up to, but not including, 5.5; 5.10.241 up to, but not including, 5.11; 5.15.190 up to, but not including, 5.16; 6.1.148 up to, but not including, 6.2; 6.6.102 up to, but not including, 6.7; 6.12.42 up to, but not including, 6.13 | 5.5, 5.11, 5.16, 6.2, 6.7, 6.13 |
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: wifi: iwlwifi: Fix error code in iwl_op_mode_dvm_start() Preserve the error code if iwl_setup_deferred_work() fails. The current code returns ERR_PTR(0) (which is NULL) on this path. I believe the missing error code potentially leads to a use after free involving debugfs.
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
Other references
Recent Use After Free vulnerabilities
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