CVE-2025-40305 Affecting kernel-devel package, versions *


Severity

Recommended
medium

Based on CentOS security rating.

Threat Intelligence

EPSS
0.02% (4th percentile)

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  • Snyk IDSNYK-CENTOS6-KERNELDEVEL-14241899
  • published9 Dec 2025
  • disclosed8 Dec 2025

Introduced: 8 Dec 2025

NewCVE-2025-40305  (opens in a new tab)

How to fix?

There is no fixed version for Centos:6 kernel-devel.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-devel package and not the kernel-devel package as distributed by Centos. See How to fix? for Centos:6 relevant fixed versions and status.

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

9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN

p9_read_work() doesn't set Rworksched and doesn't do schedule_work(m->rq) if list_empty(&m->req_list).

However, if the pipe is full, we need to read more data and this used to work prior to commit aaec5a95d59615 ("pipe_read: don't wake up the writer if the pipe is still full").

p9_read_work() does p9_fd_read() -> ... -> anon_pipe_read() which (before the commit above) triggered the unnecessary wakeup. This wakeup calls p9_pollwake() which kicks p9_poll_workfn() -> p9_poll_mux(), p9_poll_mux() will notice EPOLLIN and schedule_work(&m->rq).

This no longer happens after the optimization above, change p9_fd_request() to use p9_poll_mux() instead of only checking for EPOLLOUT.

CVSS Base Scores

version 3.1