Linux: Use After Free
CVE-2025-38653 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 c35b0feb80b48720dfbbf4e33759c7be3faaebb6, 33c778ea0bd0fa62ff590497e72562ff90f82b13, fc1072d934f687e1221d685cf1a49a5068318f34 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 c35b0feb80b48720dfbbf4e33759c7be3faaebb6 or 33c778ea0bd0fa62ff590497e72562ff90f82b13 or fc1072d934f687e1221d685cf1a49a5068318f34 or d136502e04d8853a9aecb335d07bbefd7a1519a8, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.148 or 6.6.102 or 6.12.42 or 6.15.10, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 3f61631d47f115b83c935d0039f95cb68b0c8ab7 up to, but not including, c35b0feb80b48720dfbbf4e33759c7be3faaebb6; 3f61631d47f115b83c935d0039f95cb68b0c8ab7 up to, but not including, 33c778ea0bd0fa62ff590497e72562ff90f82b13; 3f61631d47f115b83c935d0039f95cb68b0c8ab7 up to, but not including, fc1072d934f687e1221d685cf1a49a5068318f34; 3f61631d47f115b83c935d0039f95cb68b0c8ab7 up to, but not including, d136502e04d8853a9aecb335d07bbefd7a1519a8; 3f61631d47f115b83c935d0039f95cb68b0c8ab7 up to, but not including, 1fccbfbae1dd36198dc47feac696563244ad81d3; 3f61631d47f115b83c935d0039f95cb68b0c8ab7 up to, but not including, ff7ec8dc1b646296f8d94c39339e8d3833d16c05; 6.0 | c35b0feb80b48720dfbbf4e33759c7be3faaebb6, 33c778ea0bd0fa62ff590497e72562ff90f82b13, fc1072d934f687e1221d685cf1a49a5068318f34, d136502e04d8853a9aecb335d07bbefd7a1519a8, 1fccbfbae1dd36198dc47feac696563244ad81d3, ff7ec8dc1b646296f8d94c39339e8d3833d16c05 |
| Linux | Linux Kernel | 6.0 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 | 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: proc: use the same treatment to check proc_lseek as ones for proc_read_iter et.al Check pde->proc_ops->proc_lseek directly may cause UAF in rmmod scenario. It's a gap in proc_reg_open() after commit 654b33ada4ab("proc: fix UAF in proc_get_inode()"). Followed by AI Viro's suggestion, fix it in same manner.
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.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/1fccbfbae1dd36198dc47feac696563244ad81d3
- git.kernel.org/stable/c/33c778ea0bd0fa62ff590497e72562ff90f82b13
- git.kernel.org/stable/c/c35b0feb80b48720dfbbf4e33759c7be3faaebb6
- git.kernel.org/stable/c/d136502e04d8853a9aecb335d07bbefd7a1519a8
- git.kernel.org/stable/c/fc1072d934f687e1221d685cf1a49a5068318f34
- git.kernel.org/stable/c/ff7ec8dc1b646296f8d94c39339e8d3833d16c05
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
- 7.8 High severity
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