CVE-2025-21672

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

afs: Fix merge preference rule failure condition

syzbot reported a lock held when returning to userspace[1]. This is because if argc is less than 0 and the function returns directly, the held inode lock is not released.

Fix this by store the error in ret and jump to done to clean up instead of returning directly.

[dh: Modified Lizhi Xu's original patch to make it honour the error code from afs_split_string()]

[1] WARNING: lock held when returning to user space! 6.13.0-rc3-syzkaller-00209-g499551201b5f #0 Not tainted

syz-executor133/5823 is leaving the kernel with locks still held! 1 lock held by syz-executor133/5823: #0: ffff888071cffc00 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:818 [inline] #0: ffff888071cffc00 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: afs_proc_addr_prefs_write+0x2bb/0x14e0 fs/afs/addr_prefs.c:388

This vulnerability is rated as having a Moderate impact because exploitation is confined to local authenticated users and is limited to a denial of service without compromising confidentiality or system integrity. In default Red Hat Enterprise Linux deployments, the in-kernel AFS filesystem module is not loaded, substantially reducing the surface of exposure for standard installations. Exploitation requires interacting with the specific AFS procfs configuration interface, meaning systems that do not mount or configure AFS shares are unaffected.

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.