Linux: Use After Free
CVE-2025-38703 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 b17fcce70733c211cb5dabf54f4f9491920b1d92, ba37807d08bae67de6139346a85650cab5f6145a, 683b0e397dad9f26a42dcacf6f7f545a77ce6c06 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 0.18% 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 b17fcce70733c211cb5dabf54f4f9491920b1d92 or ba37807d08bae67de6139346a85650cab5f6145a or 683b0e397dad9f26a42dcacf6f7f545a77ce6c06 or 6bd90e700b4285e6a7541e00f969cab0d696adde, 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 | dd08ebf6c3525a7ea2186e636df064ea47281987 up to, but not including, b17fcce70733c211cb5dabf54f4f9491920b1d92; dd08ebf6c3525a7ea2186e636df064ea47281987 up to, but not including, ba37807d08bae67de6139346a85650cab5f6145a; dd08ebf6c3525a7ea2186e636df064ea47281987 up to, but not including, 683b0e397dad9f26a42dcacf6f7f545a77ce6c06; dd08ebf6c3525a7ea2186e636df064ea47281987 up to, but not including, 6bd90e700b4285e6a7541e00f969cab0d696adde; 6.8 | b17fcce70733c211cb5dabf54f4f9491920b1d92, ba37807d08bae67de6139346a85650cab5f6145a, 683b0e397dad9f26a42dcacf6f7f545a77ce6c06, 6bd90e700b4285e6a7541e00f969cab0d696adde |
| Linux | Linux Kernel | 6.8 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 | 6.12.43, 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: drm/xe: Make dma-fences compliant with the safe access rules Xe can free some of the data pointed to by the dma-fences it exports. Most notably the timeline name can get freed if userspace closes the associated submit queue. At the same time the fence could have been exported to a third party (for example a sync_fence fd) which will then cause an use- after-free on subsequent access. To make this safe we need to make the driver compliant with the newly documented dma-fence rules. Driver has to ensure a RCU grace period between signalling a fence and freeing any data pointed to by said fence. For the timeline name we simply make the queue be freed via kfree_rcu and for the shared lock associated with multiple queues we add a RCU grace period before freeing the per GT structure holding the lock.
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
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
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