Linux: Use After Free
CVE-2025-68822 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 55beb00222af2eee967322670a0c8f3c6426becb, b9d8cfd6d77f5072a4df10646810d128220457fb, ed8c61b89be0c45f029228b2913d5cf7b5cda1a7 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 55beb00222af2eee967322670a0c8f3c6426becb or b9d8cfd6d77f5072a4df10646810d128220457fb or ed8c61b89be0c45f029228b2913d5cf7b5cda1a7 or a9c115e017b2c633d25bdfe6709dda6fc36f08c2, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 04aae283ba6a8cd4851d937bf9c6d6ef0361d794 up to, but not including, 55beb00222af2eee967322670a0c8f3c6426becb; 04aae283ba6a8cd4851d937bf9c6d6ef0361d794 up to, but not including, b9d8cfd6d77f5072a4df10646810d128220457fb; 04aae283ba6a8cd4851d937bf9c6d6ef0361d794 up to, but not including, ed8c61b89be0c45f029228b2913d5cf7b5cda1a7; 04aae283ba6a8cd4851d937bf9c6d6ef0361d794 up to, but not including, a9c115e017b2c633d25bdfe6709dda6fc36f08c2; 04aae283ba6a8cd4851d937bf9c6d6ef0361d794 up to, but not including, bf40644ef8c8a288742fa45580897ed0e0289474; 4.0 | 55beb00222af2eee967322670a0c8f3c6426becb, b9d8cfd6d77f5072a4df10646810d128220457fb, ed8c61b89be0c45f029228b2913d5cf7b5cda1a7, a9c115e017b2c633d25bdfe6709dda6fc36f08c2, bf40644ef8c8a288742fa45580897ed0e0289474 |
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 CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: Input: alps - fix use-after-free bugs caused by dev3_register_work The dev3_register_work delayed work item is initialized within alps_reconnect() and scheduled upon receipt of the first bare PS/2 packet from an external PS/2 device connected to the ALPS touchpad. During device detachment, the original implementation calls flush_workqueue() in psmouse_disconnect() to ensure completion of dev3_register_work. However, the flush_workqueue() in psmouse_disconnect() only blocks and waits for work items that were already queued to the workqueue prior to its invocation. Any work items submitted after flush_workqueue() is called are not included in the set of tasks that the flush operation awaits. This means that after flush_workqueue() has finished executing, the dev3_register_work could still be scheduled. Although the psmouse state is set to PSMOUSE_CMD_MODE in psmouse_disconnect(), the scheduling of dev3_register_work remains unaffected. The race condition can occur as follows: CPU 0 (cleanup path) | CPU 1 (delayed work) psmouse_disconnect() | psmouse_set_state() | flush_workqueue() | alps_report_bare_ps2_packet() alps_disconnect() | psmouse_queue_work() kfree(priv); // FREE | alps_register_bare_ps2_mouse() | priv = container_of(work...); // USE | priv->dev3 // USE Add disable_delayed_work_sync() in alps_disconnect() to ensure that dev3_register_work is properly canceled and prevented from executing after the alps_data structure has been deallocated. This bug is identified by static analysis.
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
Other references
- git.kernel.org/stable/c/55beb00222af2eee967322670a0c8f3c6426becb
- git.kernel.org/stable/c/a9c115e017b2c633d25bdfe6709dda6fc36f08c2
- git.kernel.org/stable/c/b9d8cfd6d77f5072a4df10646810d128220457fb
- git.kernel.org/stable/c/bf40644ef8c8a288742fa45580897ed0e0289474
- git.kernel.org/stable/c/ed8c61b89be0c45f029228b2913d5cf7b5cda1a7
Recent Use After Free vulnerabilities
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- 7.8 High severity
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- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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