Description
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 products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 5.3 | 6.6.143 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 6.18.3-1 | — |
| Debian 13 | linux | 6.12.94-1 | — |
| Debian 12 | linux | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 24.04 LTS | linux-bluefield | 6.8.0-1032.37 | — |
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | No fix yet | — |
| Ubuntu 25.10 | linux | 6.17.0-22.22 | USN-8177-1 |
| Ubuntu 25.10 | linux-aws +1 | 6.17.0-1012.12 | USN-8183-2, USN-8183-1 |
| Ubuntu 25.10 | linux-azure +1 | 6.17.0-1013.13 | USN-8245-1 |
| Ubuntu 25.10 | linux-azure-fde | No fix yet | — |
| Ubuntu 25.10 | linux-oracle | 6.17.0-1011.11 | USN-8183-2 |
| Ubuntu 25.10 | linux-realtime | 6.17.0-1010.11 | USN-8177-1 |
| Ubuntu 25.10 | linux-riscv | 6.17.0-22.22.1 | — |
| Ubuntu 24.04 LTS | linux | 6.8.0-146.146 | USN-8903-1 |
| Ubuntu 24.04 LTS | linux-aws | 6.8.0-1066.69 | USN-8903-1 |
| Ubuntu 24.04 LTS | linux-aws-6.17 +1 | 6.17.0-1012.12~24.04.1 | USN-8183-2, USN-8183-1 |
| Ubuntu 24.04 LTS | linux-azure-6.17 | 6.17.0-1013.13~24.04.1 | USN-8245-1 |
| Ubuntu 24.04 LTS | linux-azure-fde | 6.8.0-1068.75 | USN-8904-1 |
| Ubuntu 24.04 LTS | linux-gcp +1 | 6.8.0-1070.78 | USN-8905-2, USN-8904-1 |
| Ubuntu 24.04 LTS | linux-gke | 6.8.0-1065.73 | USN-8903-2 |
| Ubuntu 24.04 LTS | linux-gkeop | 6.8.0-1051.55 | USN-8903-2 |
| Ubuntu 24.04 LTS | linux-hwe-6.17 | 6.17.0-22.22~24.04.1 | USN-8183-2 |
| Ubuntu 24.04 LTS | linux-ibm | 6.8.0-1066.67 | USN-8903-2 |
| Ubuntu 24.04 LTS | linux-lowlatency | 6.8.0-146.146.1 | USN-8903-2 |
| Ubuntu 24.04 LTS | linux-nvidia | 6.8.0-1064.67 | USN-8903-2 |
| Ubuntu 24.04 LTS | linux-nvidia-6.17 | 6.17.0-1018.18 | — |
| Ubuntu 24.04 LTS | linux-nvidia-lowlatency | 6.8.0-1064.67.1 | USN-8903-2 |
| Ubuntu 24.04 LTS | linux-nvidia-tegra | 6.8.0-1038.42 | USN-9002-1 |
| Ubuntu 24.04 LTS | linux-oem-6.17 | 6.17.0-1020.20 | USN-8245-1 |
| Ubuntu 24.04 LTS | linux-oracle | 6.8.0-1063.66 | USN-8903-2 |
| Ubuntu 24.04 LTS | linux-oracle-6.17 | 6.17.0-1011.11~24.04.1 | USN-8183-2 |
| Ubuntu 24.04 LTS | linux-raspi | 6.8.0-1068.72 | USN-9025-1 |
| Ubuntu 24.04 LTS | linux-riscv +21 | No fix yet | — |
| Ubuntu 24.04 LTS | linux-riscv-6.17 | 6.17.0-22.22.1~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-vmware | 6.8.0-1008.8 | — |
| Ubuntu 22.04 LTS | linux +49 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-aws-6.8 | 6.8.0-1066.69~22.04.1 | USN-8903-1 |
| Ubuntu 22.04 LTS | linux-azure-fde-6.8 | 6.8.0-1068.75~22.04.1 | USN-8904-1 |
| Ubuntu 22.04 LTS | linux-gcp-6.8 +1 | 6.8.0-1070.78~22.04.1 | USN-8905-1, USN-8904-1 |
| Ubuntu 22.04 LTS | linux-hwe-6.8 | 6.8.0-149.149~22.04.1 | USN-9066-1 |
| Ubuntu 22.04 LTS | linux-ibm-6.8 | 6.8.0-1066.67~22.04.1 | USN-8906-1 |
| Ubuntu 22.04 LTS | linux-lowlatency-hwe-6.8 | 6.8.0-146.146.1~22.04.1 | USN-8903-2 |
| Ubuntu 22.04 LTS | linux-nvidia-6.8 | 6.8.0-1064.67~22.04.1 | USN-8903-2 |
| Ubuntu 22.04 LTS | linux-oracle-6.8 | 6.8.0-1067.71~22.04.1 | USN-9025-1 |
| Ubuntu 22.04 LTS | linux-riscv-6.8 | 6.8.0-146.146~22.04.1 | — |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-raspi-realtime | 6.8.0-2056.58 | USN-9025-1 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime | 6.8.1-1061.62 | USN-8903-1 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.14 | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.17 | 6.17.0-1010.11~24.04.1 | USN-8177-2 |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime +1 | No fix yet | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime-6.8 | 6.8.1-1061.62~22.04.1 | USN-8903-1 |
| Ubuntu Pro FIPS 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-aws-fips | 6.8.0-1066.69+fips1 | USN-8903-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-azure-fips | 6.8.0-1069.77+fips1 | USN-8904-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-fips | 6.8.0-146.146+fips1 | USN-8903-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-gcp-fips | 6.8.0-1070.78+fips1 | USN-8905-1 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-preview 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux +21 | No fix yet | — |
| Ubuntu Pro 18.04 LTS | linux-aws-5.4 +6 | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | kernel-64kb +6 | 6.4.0-150700.53.31.1 | SUSE-SU-2026:0447-1 |
| SLES 15 SP7 | kernel-azure +2 | 6.4.0-150700.20.27.1 | SUSE-SU-2026:0472-1 |
| SLES 15 SP7 | kernel-default-base | 6.4.0-150700.53.31.1.150700.17.21.1 | SUSE-SU-2026:0447-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | kernel-64kb +8 | 6.12.0-160000.26.1 | SUSE-SU-2026:20599-1 |
| SLES for SAP 16.0 | kernel-default-base | 6.12.0-160000.26.1.160000.2.7 | SUSE-SU-2026:20599-1 |
| SLES 16.0 | kernel-64kb +8 | 6.12.0-160000.26.1 | SUSE-SU-2026:20615-1, SUSE-SU-2026:20599-1 |
| SLES 16.0 | kernel-default-base | 6.12.0-160000.26.1.160000.2.7 | SUSE-SU-2026:20599-1 |
| SLE Micro 6.2 | kernel-default-base | 6.12.0-160000.26.1.160000.2.7 | SUSE-SU-2026:20555-1 |
| SLE Micro 6.2 | kernel-rt +5 | 6.12.0-160000.26.1 | SUSE-SU-2026:20570-1, SUSE-SU-2026:20555-1 |
| SLE Micro 6.1 | kernel-default-base | 6.4.0-39.1.21.16 | SUSE-SU-2026:20498-1 |
| SLE Micro 6.1 | kernel-rt +1 | 6.4.0-40.1 | SUSE-SU-2026:20876-1 |
| SLE Micro 6.1 | kernel-source +2 | 6.4.0-39.1 | SUSE-SU-2026:20498-1 |
| SLE Micro 6.0 | kernel-default-base | 6.4.0-39.1.21.16 | SUSE-SU-2026:20477-1 |
| SLE Micro 6.0 | kernel-rt +1 | 6.4.0-40.1 | SUSE-SU-2026:20845-1 |
| SLE Micro 6.0 | kernel-source +2 | 6.4.0-39.1 | SUSE-SU-2026:20477-1 |
| SLE Live Patching 15 SP7 | kernel-default | 6.4.0-150700.53.31.1 | SUSE-SU-2026:0447-1 |
| SLE Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7-RT_Update_9 | 1-150700.1.3.2 | SUSE-SU-2026:0587-1 |
| SLE Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7_Update_9 | 1-150700.15.3.1 | SUSE-SU-2026:0447-1 |
| SUSE Real Time Module 15 SP7 | kernel-rt | 6.4.0-150700.7.31.2 | SUSE-SU-2026:0587-1 |
| SUSE Real Time Module 15 SP7 | kernel-syms-rt +1 | 6.4.0-150700.7.31.1 | SUSE-SU-2026:0587-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | kernel-default-base | 6.12.0-160000.26.1.160000.2.7 | openSUSE-SU-2026:20287-1 |
| openSUSE Leap 16.0 | kernel-rt +11 | 6.12.0-160000.26.1 | openSUSE-SU-2026:20287-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | kernel | 6.6.143.1-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | kernel-uek +34 | 6.12.0-206.104.3.3.el10uek | ELSA-2026-500248 |
Advisories 28
- USN-9066-1 linux-hwe-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- WID-SEC-2026-0086 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- USN-9025-1 linux-oracle-6.8, linux-raspi, linux-raspi-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9002-1 linux-nvidia-tegra vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8903-2 linux-gke, linux-gkeop, linux-ibm, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-nvidia, linux-nvidia-6.8, linux-nvidia-lowlatency, linux-oracle vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8903-1 linux, linux-aws, linux-aws-6.8, linux-aws-fips, linux-fips, linux-realtime, linux-realtime-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8904-1 linux-azure, linux-azure-6.8, linux-azure-fde, linux-azure-fde-6.8, linux-azure-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8905-2 linux-gcp vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8905-1 linux-gcp-6.8, linux-gcp-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8906-1 linux-ibm-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 9, 2026
- USN-8183-2 linux-aws, linux-aws-6.17, linux-hwe-6.17, linux-oracle, linux-oracle-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8183-1 linux-gcp, linux-gcp-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8245-1 linux-azure, linux-azure-6.17, linux-oem-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8177-2 linux-realtime-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8177-1 linux, linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- ELSA-2026-500248 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Sep 4, 2026
- SUSE-SU-2026:20570-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Jul 9, 2026
- SUSE-SU-2026:20876-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 31, 2026
- SUSE-SU-2026:20845-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 28, 2026
- openSUSE-SU-2026:20287-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20615-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20599-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20555-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20498-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20477-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:0587-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:0472-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:0447-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026