Linux: Use After Free
CVE-2025-71073 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 fb76f871d6155c52ccc0401bbde77dd20b83d0c1, 8cf889d45bbc8477206dda78c8f757ea8ff68213, 3a7cd1397c209076c371d53bf39a55c138f62342 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 fb76f871d6155c52ccc0401bbde77dd20b83d0c1 or 8cf889d45bbc8477206dda78c8f757ea8ff68213 or 3a7cd1397c209076c371d53bf39a55c138f62342 or cffc4e29b1e2d44ab094cf142d7c461ff09b9104, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.64 or 6.18.3, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, fb76f871d6155c52ccc0401bbde77dd20b83d0c1; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 8cf889d45bbc8477206dda78c8f757ea8ff68213; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 3a7cd1397c209076c371d53bf39a55c138f62342; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, cffc4e29b1e2d44ab094cf142d7c461ff09b9104; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, e58c88f0cb2d8ed89de78f6f17409d29cfab6c5c; 2.6.12 | fb76f871d6155c52ccc0401bbde77dd20b83d0c1, 8cf889d45bbc8477206dda78c8f757ea8ff68213, 3a7cd1397c209076c371d53bf39a55c138f62342, cffc4e29b1e2d44ab094cf142d7c461ff09b9104, e58c88f0cb2d8ed89de78f6f17409d29cfab6c5c |
| Linux | Linux Kernel | 2.6.12.1 up to, but not including, 6.12.64; 6.13 up to, but not including, 6.18.3; 2.6.12; 6.19 | 6.12.64, 6.18.3 |
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.
Official description
In the Linux kernel, the following vulnerability has been resolved: Input: lkkbd - disable pending work before freeing device lkkbd_interrupt() schedules lk->tq via schedule_work(), and the work handler lkkbd_reinit() dereferences the lkkbd structure and its serio/input_dev fields. lkkbd_disconnect() and error paths in lkkbd_connect() free the lkkbd structure without preventing the reinit work from being queued again until serio_close() returns. This can allow the work handler to run after the structure has been freed, leading to a potential use-after-free. Use disable_work_sync() instead of cancel_work_sync() to ensure the reinit work cannot be re-queued, and call it both in lkkbd_disconnect() and in lkkbd_connect() error paths after serio_open().
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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