CVE-2025-68768
NoneCVSS
—
EPSS
0.2%
Published
Jan 13, 2026
CISA due date
—
The record
In the Linux kernel, the following vulnerability has been resolved: inet: frags: flush pending skbs in fqdir_pre_exit() We have been seeing occasional deadlocks on pernet_ops_rwsem since September in NIPA. The stuck task was usually modprobe (often loading a driver like ipvlan), trying to take the lock as a Writer. lockdep does not track readers for rwsems so the read wasn't obvious from the reports. On closer inspection the Reader holding the lock was conntrack looping forever in nf_conntrack_cleanup_net_list(). Based on past experience with occasional NIPA crashes I looked thru the tests which run before the crash and noticed that the crash follows ip_defrag.sh. An immediate red flag. Scouring thru (de)fragmentation queues reveals skbs sitting around, holding conntrack references. The problem is that since conntrack depends on nf_defrag_ipv6, nf_defrag_ipv6 will load first. Since nf_defrag_ipv6 loads first its netns exit hooks run _after_ conntrack's netns exit hook. Flush all fragment queue SKBs during fqdir_pre_exit() to release conntrack references before conntrack cleanup runs. Also flush the queues in timer expiry handlers when they discover fqdir->dead is set, in case packet sneaks in while we're running the pre_exit flush. The commit under Fixes is not exactly the culprit, but I think previously the timer firing would eventually unblock the spinning conntrack.
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| Linux | Kernel | 5.3.0 | 6.18.3 |
| openSUSE:Leap 16.0 | dtb-aarch64 | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-64kb | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-azure | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-default | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-default-base | 0 | 6.12.0-160000.26.1.160000.2.7 |
| openSUSE:Leap 16.0 | kernel-docs | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-kvmsmall | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-obs-build | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-obs-qa | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-rt | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-source | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-syms | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-zfcpdump | 0 | 6.12.0-160000.26.1 |
Related vulnerabilities
- CVE-2026-23226 In the Linux kernel, the following vulnerability has been resolved: ksmbd: add chann_lock… Also affects Kernel
- CVE-2026-23225 In the Linux kernel, the following vulnerability has been resolved: sched/mmcid: Don't… Also affects Kernel
- CVE-2026-23230 In the Linux kernel, the following vulnerability has been resolved: smb: client: split… Also affects Kernel
- CVE-2026-23224 In the Linux kernel, the following vulnerability has been resolved: erofs: fix UAF issue… Also affects Kernel
- CVE-2026-23227 In the Linux kernel, the following vulnerability has been resolved: drm/exynos: vidi: use… Also affects Kernel
- CVE-2026-23223 In the Linux kernel, the following vulnerability has been resolved: xfs: fix UAF in… Also affects Kernel
- CVE-2026-23228 In the Linux kernel, the following vulnerability has been resolved: smb: server: fix leak… Also affects Kernel
- CVE-2026-23229 In the Linux kernel, the following vulnerability has been resolved: crypto: virtio - Add… Also affects Kernel