CVE-2025-40203

A flaw was found in the Linux kernel’s listmount() function: the code calls path_put() while holding the namespace semaphore. Under certain conditions, this can drop the final reference to a path object inappropriately, leading to unstable behavior in mount/namespace operations.

This vulnerability is evaluated as Moderate because exploitation requires local user access and specific concurrent mount namespace conditions to induce kernel instability or a denial of service. An unprivileged local process can only trigger the flaw by exercising the listmount system call during the release of the final reference on an active path object. Because the issue cannot be exploited remotely and does not directly permit privilege escalation or information leakage, typical enterprise deployments face contained operational risk.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.