Linux: Use After Free
CVE-2026-31473 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 331242998a7ade5c2f65e14988901614629f3db5, 2c685e99efb3b3bd2b78699fba6b1cf321975db0, 585fd9a2063dacce8b2820f675ef23d5d17434c5 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 0.1% 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 331242998a7ade5c2f65e14988901614629f3db5 or 2c685e99efb3b3bd2b78699fba6b1cf321975db0 or 585fd9a2063dacce8b2820f675ef23d5d17434c5 or 1a0d9083c24fbd5d22f7100f09d11e4d696a5f01, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.253 or 5.15.203 or 6.1.168 or 6.6.131, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 6093d3002eabd7c2913d97f1d1f4ce34b072acf9 up to, but not including, 331242998a7ade5c2f65e14988901614629f3db5; 6093d3002eabd7c2913d97f1d1f4ce34b072acf9 up to, but not including, 2c685e99efb3b3bd2b78699fba6b1cf321975db0; 6093d3002eabd7c2913d97f1d1f4ce34b072acf9 up to, but not including, 585fd9a2063dacce8b2820f675ef23d5d17434c5; 6093d3002eabd7c2913d97f1d1f4ce34b072acf9 up to, but not including, 1a0d9083c24fbd5d22f7100f09d11e4d696a5f01; 6093d3002eabd7c2913d97f1d1f4ce34b072acf9 up to, but not including, d8549a453d5bdc0a71de66ad47a1106703406a56; 6093d3002eabd7c2913d97f1d1f4ce34b072acf9 up to, but not including, 72b9e81e0203f03c40f3adb457f55bd4c8eb112d; 6093d3002eabd7c2913d97f1d1f4ce34b072acf9 up to, but not including, cf2023e84f0888f96f4b65dc0804e7f3651969c1; 6093d3002eabd7c2913d97f1d1f4ce34b072acf9 up to, but not including, bef4f4a88b73e4cc550d25f665b8a9952af22773; and 1 more ranges | 331242998a7ade5c2f65e14988901614629f3db5, 2c685e99efb3b3bd2b78699fba6b1cf321975db0, 585fd9a2063dacce8b2820f675ef23d5d17434c5, 1a0d9083c24fbd5d22f7100f09d11e4d696a5f01, d8549a453d5bdc0a71de66ad47a1106703406a56, 72b9e81e0203f03c40f3adb457f55bd4c8eb112d |
| Linux | Linux Kernel | 4.20.1 up to, but not including, 5.10.253; 5.11 up to, but not including, 5.15.203; 5.16 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; 4.20; and 1 more ranges | 5.10.253, 5.15.203, 6.1.168, 6.6.131, 6.12.80, 6.18.21 |
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: media: mc, v4l2: serialize REINIT and REQBUFS with req_queue_mutex MEDIA_REQUEST_IOC_REINIT can run concurrently with VIDIOC_REQBUFS(0) queue teardown paths. This can race request object cleanup against vb2 queue cancellation and lead to use-after-free reports. We already serialize request queueing against STREAMON/OFF with req_queue_mutex. Extend that serialization to REQBUFS, and also take the same mutex in media_request_ioctl_reinit() so REINIT is in the same exclusion domain. This keeps request cleanup and queue cancellation from running in parallel for request-capable devices.
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/1a0d9083c24fbd5d22f7100f09d11e4d696a5f01
- git.kernel.org/stable/c/2c685e99efb3b3bd2b78699fba6b1cf321975db0
- git.kernel.org/stable/c/331242998a7ade5c2f65e14988901614629f3db5
- git.kernel.org/stable/c/585fd9a2063dacce8b2820f675ef23d5d17434c5
- git.kernel.org/stable/c/72b9e81e0203f03c40f3adb457f55bd4c8eb112d
- git.kernel.org/stable/c/bef4f4a88b73e4cc550d25f665b8a9952af22773
- git.kernel.org/stable/c/cf2023e84f0888f96f4b65dc0804e7f3651969c1
- git.kernel.org/stable/c/d8549a453d5bdc0a71de66ad47a1106703406a56
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 9.8 Critical severity
- 7.8 High severity
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