Linux Kernel up to 6.18.21/6.19.11 crypto algif_aead privilege escalation

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.18.21/6.19.11. It has been declared as critical. This affects the function algif_aead of the component crypto. Such manipulation leads to an unknown weakness. This vulnerability is traded as CVE-2026-31431. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.21/6.19.11. It has been rated as critical. Affected by this issue is the function algif_aead of the component crypto. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: crypto: algif_aead - Revert to operating out-of-place This mostly reverts commit 72548b093ee3 except for the copying of the associated data. There is no benefit in operating in-place in algif_aead since the source and destination come from different mappings. Get rid of all the complexity added for in-place operation and just copy the AD directly.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-31431 since 03/09/2026. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 04/23/2026).

The vulnerability scanner Nessus provides a plugin with the ID 309203 (Linux Distros Unpatched Vulnerability : CVE-2026-31431), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.18.22 or 6.19.12 eliminates this vulnerability. Applying the patch fafe0fa2995a0f7073c1c358d7d3145bcc9aedd8/ce42ee423e58dffa5ec03524054c9d8bfd4f6237/a664bf3d603dc3bdcf9ae47cc21e0daec706d7a5 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (309203). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.19.0
• 6.19.1
• 6.19.2
• 6.19.3
• 6.19.4
• 6.19.5
• 6.19.6
• 6.19.7
• 6.19.8
• 6.19.9
• 6.19.10
• 6.19.11

License

• open-source

Website

• Vendor: https://www.kernel.org/

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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