CVE-2025-23138

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

watch_queue: fix pipe accounting mismatch

Currently, watch_queue_set_size() modifies the pipe buffers charged to

user->pipe_bufs without updating the pipe->nr_accounted on the pipe

itself, due to the if (!pipe_has_watch_queue()) test in

pipe_resize_ring(). This means that when the pipe is ultimately freed,

we decrement user->pipe_bufs by something other than what than we had

charged to it, potentially leading to an underflow. This in turn can

cause subsequent too_many_pipe_buffers_soft() tests to fail with -EPERM.

To remedy this, explicitly account for the pipe usage in

watch_queue_set_size() to match the number set via account_pipe_buffers()

(It's unclear why watch_queue_set_size() does not update nr_accounted;

it may be due to intentional overprovisioning in watch_queue_set_size()?)

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References