Linux Kernel up to 7.2.5 xenbus xenbus_dev_changed deadlock

Summaryinfo

A vulnerability labeled as critical has been found in Linux Kernel up to 7.2.5. Affected by this issue is the function xenbus_dev_changed of the component xenbus. The manipulation results in deadlock. This vulnerability is identified as CVE-2026-90310. The attack can be executed remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 7.2.5. Affected is the function xenbus_dev_changed of the component xenbus. The manipulation with an unknown input leads to a deadlock vulnerability. CWE is classifying the issue as CWE-833. The product contains multiple threads or executable segments that are waiting for each other to release a necessary lock, resulting in deadlock. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: xen/xenbus: check otherend_id only after it has been initialized When device just got initialized (for example on module load), the otherend_id field is initialized only after xenbus_read_otherend_details() gets called. If xenstore watch triggers xenbus_dev_changed() before that, it might consider still zeroed otherend_id field (not matching actual xenstore content) as a sign of device state reset. It can happen because xenstore watch are handled in another thread (xenwatch), which can run in parallel to the initial device probe running at module load. In that case, it would call device_unregister(), which would deadlock against device probe from module init. Fix this by considering dev->otherend_id change only after dev->otherend is set (which happen after otherend_id is initialized).

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-90310 since 09/11/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. 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 09/17/2026). The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch 36fb592af353c55832e2cafe3fcfc3291be05f19/c76cbf348c7df077f93fa99a1225a527ce64cfa1 is able to eliminate this problem. 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

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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