Linux: Use After Free
CVE-2026-31493 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 8c24b5179af260a5f36571c992d29aab1f448544, 7ba09d85f177e9f5f64b881f33dbcb57b2cf23d5, 0dd98aea1c0c45987fa2dd92f988b0eb1a72c125 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 0.16% 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 8c24b5179af260a5f36571c992d29aab1f448544 or 7ba09d85f177e9f5f64b881f33dbcb57b2cf23d5 or 0dd98aea1c0c45987fa2dd92f988b0eb1a72c125 or 1cf95fe5dc5471efea947b4c6f8913da6bc7976e, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.21 or 6.19.11, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 68fb9f3e312a36e49fd05ec2d6b668daf2c4931a up to, but not including, 8c24b5179af260a5f36571c992d29aab1f448544; 68fb9f3e312a36e49fd05ec2d6b668daf2c4931a up to, but not including, 7ba09d85f177e9f5f64b881f33dbcb57b2cf23d5; 68fb9f3e312a36e49fd05ec2d6b668daf2c4931a up to, but not including, 0dd98aea1c0c45987fa2dd92f988b0eb1a72c125; 68fb9f3e312a36e49fd05ec2d6b668daf2c4931a up to, but not including, 1cf95fe5dc5471efea947b4c6f8913da6bc7976e; 68fb9f3e312a36e49fd05ec2d6b668daf2c4931a up to, but not including, ef3b06742c8a201d0e83edc9a33a89a4fe3009f8; 5.12 | 8c24b5179af260a5f36571c992d29aab1f448544, 7ba09d85f177e9f5f64b881f33dbcb57b2cf23d5, 0dd98aea1c0c45987fa2dd92f988b0eb1a72c125, 1cf95fe5dc5471efea947b4c6f8913da6bc7976e, ef3b06742c8a201d0e83edc9a33a89a4fe3009f8 |
| Linux | Linux Kernel | 5.12.1 up to, but not including, 6.18.21; 6.19 up to, but not including, 6.19.11; 5.12; 7.0 | 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.
Official description
In the Linux kernel, the following vulnerability has been resolved: RDMA/efa: Fix use of completion ctx after free On admin queue completion handling, if the admin command completed with error we print data from the completion context. The issue is that we already freed the completion context in polling/interrupts handler which means we print data from context in an unknown state (it might be already used again). Change the admin submission flow so alloc/dealloc of the context will be symmetric and dealloc will be called after any potential use of the context.
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: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
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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