Description
net/netfilter/nf_conntrack_standalone.c in the Linux kernel before 5.12.2 allows observation of changes in any net namespace because these changes are leaked into all other net namespaces. This is related to the NF_SYSCTL_CT_MAX, NF_SYSCTL_CT_EXPECT_MAX, and NF_SYSCTL_CT_BUCKETS sysctls.
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 | 5.10.38-1 | — |
| Debian 13 | linux | 5.10.38-1 | — |
| Debian 12 | linux | 5.10.38-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | linux-azure-5.8 | 5.8.0-1036.38~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-bluefield | 5.4.0-1016.19 | — |
| Ubuntu 20.04 LTS | linux-hwe-5.8 | 5.8.0-59.66~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-oem-5.10 | 5.10.0-1029.30 | — |
| Ubuntu 20.04 LTS | linux-riscv +6 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +13 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP3 | kernel-64kb +7 | 5.3.18-59.24.1 | SUSE-SU-2021:3205-1 |
| SLES 15 SP3 | kernel-azure | 5.3.18-38.22.2 | SUSE-SU-2021:3179-1 |
| SLES 15 SP3 | kernel-default-base | 5.3.18-59.24.1.18.12.1 | SUSE-SU-2021:3205-1 |
| SLES 15 SP3 | kernel-syms-azure +1 | 5.3.18-38.22.1 | SUSE-SU-2021:3179-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLE Micro 5.1 | kernel-default | 5.3.18-59.24.1 | SUSE-SU-2021:3205-2 |
| SLE Micro 5.1 | kernel-default-base | 5.3.18-59.24.1.18.12.1 | SUSE-SU-2021:3205-2 |
| SLE Live Patching 15 SP3 | kernel-default | 5.3.18-59.24.1 | SUSE-SU-2021:3205-1 |
| SLE Live Patching 15 SP3 | kernel-livepatch-SLE15-SP3_Update_6 | 1-7.5.1 | SUSE-SU-2021:3205-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.3 | dtb-aarch64 +11 | 5.3.18-59.24.1 | openSUSE-SU-2021:3205-1 |
| openSUSE Leap 15.3 | kernel-azure | 5.3.18-38.22.2 | openSUSE-SU-2021:3179-1 |
| openSUSE Leap 15.3 | kernel-default-base | 5.3.18-59.24.1.18.12.1 | openSUSE-SU-2021:3205-1 |
| openSUSE Leap 15.3 | kernel-syms-azure +1 | 5.3.18-38.22.1 | openSUSE-SU-2021:3179-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 2 (CBL-Mariner) | kernel | 5.10.78.1-1 | — |
Advisories 5
- SUSE-SU-2021:3179-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:3179-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:3205-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:3205-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:3205-2 Security update for the Linux Kernel SUSE / openSUSE Security Updates · May 2, 2025