CVE-2025-21795

Name	CVE-2025-21795
Description	In the Linux kernel, the following vulnerability has been resolved: NFSD: fix hang in nfsd4_shutdown_callback If nfs4_client is in courtesy state then there is no point to send the callback. This causes nfsd4_shutdown_callback to hang since cl_cb_inflight is not 0. This hang lasts about 15 minutes until TCP notifies NFSD that the connection was dropped. This patch modifies nfsd4_run_cb_work to skip the RPC call if nfs4_client is in courtesy state.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DLA-4102-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
linux (PTS)	bullseye	5.10.223-1	vulnerable
	bullseye (security)	5.10.234-1	vulnerable
	bookworm	6.1.129-1	fixed
	bookworm (security)	6.1.128-1	vulnerable
	trixie	6.12.20-1	fixed
	sid	6.12.21-1	fixed
linux-6.1 (PTS)	bullseye (security)	6.1.129-1~deb11u1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Origin
linux	source	bookworm	6.1.129-1
linux	source	(unstable)	6.12.16-1
linux-6.1	source	bullseye	6.1.129-1~deb11u1	DLA-4102-1

https://git.kernel.org/linus/036ac2778f7b28885814c6fbc07e156ad1624d03 (6.14-rc3)