Linux: Use After Free
CVE-2026-31566 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 bc7760c107dc08ef3e231d72c492e67b0a86848b, e23602eb0779760544314ed3905fa6a89a4e4070, 138e42be35ff2ce6572ae744de851ea286cf3c69 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 0.13% 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 bc7760c107dc08ef3e231d72c492e67b0a86848b or e23602eb0779760544314ed3905fa6a89a4e4070 or 138e42be35ff2ce6572ae744de851ea286cf3c69 or 39820864eacd886f1a6f817414fb8f9ea3e9a2b4, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.168 or 6.6.131 or 6.12.80 or 6.18.21, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 9ae55f030dc523fc4dc6069557e4a887ea815453 up to, but not including, bc7760c107dc08ef3e231d72c492e67b0a86848b; 9ae55f030dc523fc4dc6069557e4a887ea815453 up to, but not including, e23602eb0779760544314ed3905fa6a89a4e4070; 9ae55f030dc523fc4dc6069557e4a887ea815453 up to, but not including, 138e42be35ff2ce6572ae744de851ea286cf3c69; 9ae55f030dc523fc4dc6069557e4a887ea815453 up to, but not including, 39820864eacd886f1a6f817414fb8f9ea3e9a2b4; 9ae55f030dc523fc4dc6069557e4a887ea815453 up to, but not including, 42d248726a0837640452b71c5a202ca3d35239ec; 9ae55f030dc523fc4dc6069557e4a887ea815453 up to, but not including, 7150850146ebfa4ca998f653f264b8df6f7f85be; 6.0 | bc7760c107dc08ef3e231d72c492e67b0a86848b, e23602eb0779760544314ed3905fa6a89a4e4070, 138e42be35ff2ce6572ae744de851ea286cf3c69, 39820864eacd886f1a6f817414fb8f9ea3e9a2b4, 42d248726a0837640452b71c5a202ca3d35239ec, 7150850146ebfa4ca998f653f264b8df6f7f85be |
| Linux | Linux Kernel | 6.0.1 up to, but not including, 6.1.168; 6.2 up to, but not including, 6.6.131; 6.7 up to, but not including, 6.12.80; 6.13 up to, but not including, 6.18.21; 6.19 up to, but not including, 6.19.11; 6.0; 7.0 | 6.1.168, 6.6.131, 6.12.80, 6.18.21, 6.19.11 |
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/amdgpu: Fix fence put before wait in amdgpu_amdkfd_submit_ib amdgpu_amdkfd_submit_ib() submits a GPU job and gets a fence from amdgpu_ib_schedule(). This fence is used to wait for job completion. Currently, the code drops the fence reference using dma_fence_put() before calling dma_fence_wait(). If dma_fence_put() releases the last reference, the fence may be freed before dma_fence_wait() is called. This can lead to a use-after-free. Fix this by waiting on the fence first and releasing the reference only after dma_fence_wait() completes. Fixes the below: drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c:697 amdgpu_amdkfd_submit_ib() warn: passing freed memory 'f' (line 696) (cherry picked from commit 8b9e5259adc385b61a6590a13b82ae0ac2bd3482)
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
Patches and release notes
- git.kernel.org/stable/c/138e42be35ff2ce6572ae744de851ea286cf3c69
- git.kernel.org/stable/c/39820864eacd886f1a6f817414fb8f9ea3e9a2b4
- git.kernel.org/stable/c/42d248726a0837640452b71c5a202ca3d35239ec
- git.kernel.org/stable/c/7150850146ebfa4ca998f653f264b8df6f7f85be
- git.kernel.org/stable/c/bc7760c107dc08ef3e231d72c492e67b0a86848b
- git.kernel.org/stable/c/e23602eb0779760544314ed3905fa6a89a4e4070
Recent Use After Free vulnerabilities
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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