Linux Kernel up to 7.2.6/7.3-rc1 ksmbd race condition

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2.6/7.3-rc1. It has been declared as very critical. This vulnerability affects unknown code of the component ksmbd. Such manipulation leads to race condition. This vulnerability is referenced as CVE-2026-98115. It is possible to launch the attack remotely. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.2.6/7.3-rc1. It has been rated as very critical. Affected by this issue is some unknown processing of the component ksmbd. The manipulation with an unknown input leads to a race condition vulnerability. Using CWE to declare the problem leads to CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: ksmbd: safely drain sessions during logoff SMB3 multichannel allows requests for one session to run on multiple connections. Wait for all channels bound to a session before freeing shared session objects. A deferred byte-range lock remains counted as a running request and only wakes when its file closes. Wake blocked locks during the drain without unpublishing or modifying their file objects. Synchronous CANCEL requests must invoke their cancellation callback to wake pending operations, while CHANGE_NOTIFY completion remains specific to the asynchronous path. Serialize session teardown with channel registration and previous-session cleanup, and use atomic work-state transitions so LOGOFF, CANCEL, and connection teardown invoke cancellation callbacks only once.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-98115 since 09/25/2026. The exploitation is known to be easy. The attack may be launched remotely. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/25/2026).

Upgrading to version 7.2.7 or 7.3-rc2 eliminates this vulnerability. Applying the patch a7e6df0bb92642bee4431b2b85c69ada1e463b21/d12168084c8c1b6d883c8eca5853929ac5136a9e is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5
• 7.2.6
• 7.3-rc1

License

• open-source

Website

• Vendor: https://www.kernel.org/

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