Linux: Use After Free
CVE-2025-38722 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 5b0c23e9ec3e161a893d6ff9b4fad479e4539627, d26058c2349d77d1ef179a2cc9752ca12004b6ff, c07886761fd6251db6938d4e747002e3d150d231 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 0.21% 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 5b0c23e9ec3e161a893d6ff9b4fad479e4539627 or d26058c2349d77d1ef179a2cc9752ca12004b6ff or c07886761fd6251db6938d4e747002e3d150d231 or 40deceb38f9db759772d1c289c28fd2a543f57fc, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.43 or 6.15.11 or 6.16.2, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | db1a8dd916aac986871f6b873a3aefad906f383a up to, but not including, 5b0c23e9ec3e161a893d6ff9b4fad479e4539627; db1a8dd916aac986871f6b873a3aefad906f383a up to, but not including, d26058c2349d77d1ef179a2cc9752ca12004b6ff; db1a8dd916aac986871f6b873a3aefad906f383a up to, but not including, c07886761fd6251db6938d4e747002e3d150d231; db1a8dd916aac986871f6b873a3aefad906f383a up to, but not including, 40deceb38f9db759772d1c289c28fd2a543f57fc; db1a8dd916aac986871f6b873a3aefad906f383a up to, but not including, 55c232d7e0241f1d5120b595e7a9de24c75ed3d8; db1a8dd916aac986871f6b873a3aefad906f383a up to, but not including, 33927f3d0ecdcff06326d6e4edb6166aed42811c; 5.16 | 5b0c23e9ec3e161a893d6ff9b4fad479e4539627, d26058c2349d77d1ef179a2cc9752ca12004b6ff, c07886761fd6251db6938d4e747002e3d150d231, 40deceb38f9db759772d1c289c28fd2a543f57fc, 55c232d7e0241f1d5120b595e7a9de24c75ed3d8, 33927f3d0ecdcff06326d6e4edb6166aed42811c |
| Linux | Linux Kernel | 5.16 up to, but not including, 6.12.43; 6.13 up to, but not including, 6.15.11; 6.16 up to, but not including, 6.16.2; 6.17 | 6.12.43, 6.15.11, 6.16.2 |
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: habanalabs: fix UAF in export_dmabuf() As soon as we'd inserted a file reference into descriptor table, another thread could close it. That's fine for the case when all we are doing is returning that descriptor to userland (it's a race, but it's a userland race and there's nothing the kernel can do about it). However, if we follow fd_install() with any kind of access to objects that would be destroyed on close (be it the struct file itself or anything destroyed by its ->release()), we have a UAF. dma_buf_fd() is a combination of reserving a descriptor and fd_install(). habanalabs export_dmabuf() calls it and then proceeds to access the objects destroyed on close. In particular, it grabs an extra reference to another struct file that will be dropped as part of ->release() for ours; that "will be" is actually "might have already been". Fix that by reserving descriptor before anything else and do fd_install() only when everything had been set up. As a side benefit, we no longer have the failure exit with file already created, but reference to underlying file (as well as ->dmabuf_export_cnt, etc.) not grabbed yet; unlike dma_buf_fd(), fd_install() can't fail.
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
- 8.8 High severity
Android Runtime Use-After-Free Exploited
- 8.0 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
Spotted an error? Tell us.