CVE-2025-40305

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

Loading…

Severity

Moderate

Red Hat Product Security

5.5

CVSS 3.1

Review impact separately from score.

Published · December 8, 2025

Updated · June 30, 2026

Description

A deadlock condition was found in the 9P filesystem transport layer in the Linux kernel. After a pipe optimization change, p9_fd_request() no longer properly wakes the RX thread when the pipe is full, causing the 9P protocol to stall. This results in I/O hangs on 9P-mounted filesystems.

Statement

This affects systems using 9P filesystem mounts (common in VM environments like QEMU/KVM for host-guest file sharing). The issue causes I/O stalls rather than memory corruption.

CVSS score applicability

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

No mitigation is specified in collected source.

CVSS / CWE

CVSS 3.1 · 5.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWE-833 · Deadlock