Linux Kernel up to 6.18.26/7.0.3 weighted_interleave_auto_store memory leak

Summaryinfo

A vulnerability described as critical has been identified in Linux Kernel up to 6.18.26/7.0.3. This affects the function weighted_interleave_auto_store. Executing a manipulation can lead to memory leak. This vulnerability is registered as CVE-2026-46042. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.26/7.0.3. It has been declared as critical. This vulnerability affects the function weighted_interleave_auto_store. The manipulation with an unknown input leads to a memory leak vulnerability. The CWE definition for the vulnerability is CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. As an impact it is known to affect availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: mm/mempolicy: fix memory leaks in weighted_interleave_auto_store() weighted_interleave_auto_store() fetches old_wi_state inside the if (!input) block only. This causes two memory leaks: 1. When a user writes "false" and the current mode is already manual, the function returns early without freeing the freshly allocated new_wi_state. 2. When a user writes "true", old_wi_state stays NULL because the fetch is skipped entirely. The old state is then overwritten by rcu_assign_pointer() but never freed, since the cleanup path is gated on old_wi_state being non-NULL. A user can trigger this repeatedly by writing "1" in a loop. Fix both leaks by moving the old_wi_state fetch before the input check, making it unconditional. This also allows a unified early return for both "true" and "false" when the requested mode matches the current mode. Reviewed by: Donet Tom <[email protected]>

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-46042 since 05/13/2026. There are known technical details, but no exploit is available.

Upgrading to version 6.18.27, 7.0.4 or 7.1-rc1 eliminates this vulnerability. Applying the patch c42a7efb9060d89b72708ffaf255d0002c2164a7/39caa9ca863f96b3d00447c5aa200cabda489856/6fae274ce0e3109cbbc4c18b354eaace1f0af7d7 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.

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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
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 7.0.0
• 7.0.1
• 7.0.2
• 7.0.3

License

• open-source

Website

• Vendor: https://www.kernel.org/

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