CVE-2025-38017 Affecting kernel package, versions *


Severity

Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.02% (4th percentile)

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  • Snyk IDSNYK-RHEL10-KERNEL-10492451
  • published21 Jun 2025
  • disclosed18 Jun 2025

Introduced: 18 Jun 2025

NewCVE-2025-38017  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:10 kernel.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel package and not the kernel package as distributed by RHEL. See How to fix? for RHEL:10 relevant fixed versions and status.

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

fs/eventpoll: fix endless busy loop after timeout has expired

After commit 0a65bc27bd64 ("eventpoll: Set epoll timeout if it's in the future"), the following program would immediately enter a busy loop in the kernel:

int main() {
  int e = epoll_create1(0);
  struct epoll_event event = {.events = EPOLLIN};
  epoll_ctl(e, EPOLL_CTL_ADD, 0, &event);
  const struct timespec timeout = {.tv_nsec = 1};
  epoll_pwait2(e, &event, 1, &timeout, 0);
}

This happens because the given (non-zero) timeout of 1 nanosecond usually expires before ep_poll() is entered and then ep_schedule_timeout() returns false, but timed_out is never set because the code line that sets it is skipped. This quickly turns into a soft lockup, RCU stalls and deadlocks, inflicting severe headaches to the whole system.

When the timeout has expired, we don't need to schedule a hrtimer, but we should set the timed_out variable. Therefore, I suggest moving the ep_schedule_timeout() check into the timed_out expression instead of skipping it.

brauner: Note that there was an earlier fix by Joe Damato in response to my bug report in [1].

CVSS Base Scores

version 3.1