CVE-2025-21672: afs: Fix merge preference rule failure condition
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 afssplitstring()]
[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->stype->imutexkey#9){++++}-{4:4}, at: inodelock include/linux/fs.h:818 [inline] #0: ffff888071cffc00 (&sb->stype->imutexkey#9){++++}-{4:4}, at: afsprocaddrprefswrite+0x2bb/0x14e0 fs/afs/addrprefs.c:388
Other sources
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 afssplitstring()]
[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-stype-imutexkey#9){++++}-{4:4}, at: inodelock include/linux/fs.h:818 [inline] #0: ffff888071cffc00 (&sb-stype-imutexkey#9){++++}-{4:4}, at: afsprocaddrprefswrite+0x2bb/0x14e0 fs/afs/addrprefs.c:388
— IBM
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 5.10.223-1Fixed in 5.10.234-1Fixed in 6.1.129-1Fixed in 6.1.135-1Fixed in 6.12.27-1 - Upgrade
Upgrade
linux kernelto a version that resolves this vulnerability.Fixed in 6.13.0-rc3-syzkaller-00209-g499551201b5fPatch afs: Fix merge preference rule failure condition
Event History
Frequently Asked Questions
What is the severity of CVE-2025-21672?
CVE-2025-21672 is classified as a medium-severity vulnerability in the Linux kernel.
How do I fix CVE-2025-21672?
To address CVE-2025-21672, you should upgrade to the patched version of the Linux kernel that resolves this issue.
What versions of the Linux kernel are affected by CVE-2025-21672?
CVE-2025-21672 affects Linux kernel versions prior to 6.12.11 and specific release candidates of 6.13.
What is the impact of not fixing CVE-2025-21672?
Failing to fix CVE-2025-21672 could lead to potential deadlocks and affect system stability when returning to userspace.
Who reported CVE-2025-21672?
CVE-2025-21672 was reported by syzbot, which is a system for testing the Linux kernel.