Linux: Use After Free
CVE-2025-68793 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 dac58c012c47cadf337a35eb05d44498c43e5cd0, 77f73253015cbc7893fca1821ac3eae9eb4bc943 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 0.14% 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 dac58c012c47cadf337a35eb05d44498c43e5cd0 or 77f73253015cbc7893fca1821ac3eae9eb4bc943, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | a72002cb181f350734108228b24c5d10d358f95a up to, but not including, dac58c012c47cadf337a35eb05d44498c43e5cd0; a72002cb181f350734108228b24c5d10d358f95a up to, but not including, 77f73253015cbc7893fca1821ac3eae9eb4bc943; 6.17 | dac58c012c47cadf337a35eb05d44498c43e5cd0, 77f73253015cbc7893fca1821ac3eae9eb4bc943 |
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: drm/amdgpu: fix a job->pasid access race in gpu recovery Avoid a possible UAF in GPU recovery due to a race between the sched timeout callback and the tdr work queue. The gpu recovery function calls drm_sched_stop() and later drm_sched_start(). drm_sched_start() restarts the tdr queue which will eventually free the job. If the tdr queue frees the job before time out callback completes, the job will be freed and we'll get a UAF when accessing the pasid. Cache it early to avoid the UAF. Example KASAN trace: [ 493.058141] BUG: KASAN: slab-use-after-free in amdgpu_device_gpu_recover+0x968/0x990 [amdgpu] [ 493.067530] Read of size 4 at addr ffff88b0ce3f794c by task kworker/u128:1/323 [ 493.074892] [ 493.076485] CPU: 9 UID: 0 PID: 323 Comm: kworker/u128:1 Tainted: G E 6.16.0-1289896.2.zuul.bf4f11df81c1410bbe901c4373305a31 #1 PREEMPT(voluntary) [ 493.076493] Tainted: [E]=UNSIGNED_MODULE [ 493.076495] Hardware name: TYAN B8021G88V2HR-2T/S8021GM2NR-2T, BIOS V1.03.B10 04/01/2019 [ 493.076500] Workqueue: amdgpu-reset-dev drm_sched_job_timedout [gpu_sched] [ 493.076512] Call Trace: [ 493.076515] <TASK> [ 493.076518] dump_stack_lvl+0x64/0x80 [ 493.076529] print_report+0xce/0x630 [ 493.076536] ? _raw_spin_lock_irqsave+0x86/0xd0 [ 493.076541] ? __pfx__raw_spin_lock_irqsave+0x10/0x10 [ 493.076545] ? amdgpu_device_gpu_recover+0x968/0x990 [amdgpu] [ 493.077253] kasan_report+0xb8/0xf0 [ 493.077258] ? amdgpu_device_gpu_recover+0x968/0x990 [amdgpu] [ 493.077965] amdgpu_device_gpu_recover+0x968/0x990 [amdgpu] [ 493.078672] ? __pfx_amdgpu_device_gpu_recover+0x10/0x10 [amdgpu] [ 493.079378] ? amdgpu_coredump+0x1fd/0x4c0 [amdgpu] [ 493.080111] amdgpu_job_timedout+0x642/0x1400 [amdgpu] [ 493.080903] ? pick_task_fair+0x24e/0x330 [ 493.080910] ? __pfx_amdgpu_job_timedout+0x10/0x10 [amdgpu] [ 493.081702] ? _raw_spin_lock+0x75/0xc0 [ 493.081708] ? __pfx__raw_spin_lock+0x10/0x10 [ 493.081712] drm_sched_job_timedout+0x1b0/0x4b0 [gpu_sched] [ 493.081721] ? __pfx__raw_spin_lock_irq+0x10/0x10 [ 493.081725] process_one_work+0x679/0xff0 [ 493.081732] worker_thread+0x6ce/0xfd0 [ 493.081736] ? __pfx_worker_thread+0x10/0x10 [ 493.081739] kthread+0x376/0x730 [ 493.081744] ? __pfx_kthread+0x10/0x10 [ 493.081748] ? __pfx__raw_spin_lock_irq+0x10/0x10 [ 493.081751] ? __pfx_kthread+0x10/0x10 [ 493.081755] ret_from_fork+0x247/0x330 [ 493.081761] ? __pfx_kthread+0x10/0x10 [ 493.081764] ret_from_fork_asm+0x1a/0x30 [ 493.081771] </TASK> (cherry picked from commit 20880a3fd5dd7bca1a079534cf6596bda92e107d)
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
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