CVE-2025-21886

Name of the Vulnerable Software and Affected Versions Linux kernel versions prior to 6.12.0-rc7+

Description A vulnerability in the Linux kernel has been resolved, specifically in the RDMA/mlx5 component. The issue was related to an implicit ODP hang on parent deregistration. The problem occurred because the reference count for the implicit MR parent was not properly managed, leading to a potential hang during parent deregistration. The code has been updated to properly manage the reference count.

Recommendations For Linux kernel versions prior to 6.12.0-rc7+, update to a newer version to resolve the issue. As a temporary workaround, consider disabling the destroy unused implicit child mr() function until a patch is available. Restrict access to the ib uverbs module to minimize the risk of exploitation. Avoid using the ib dereg mr user function in the affected API endpoint until the issue is resolved.