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High · 7.8 CVE-2026-53267 EUVD-2026-39218GHSA-mrf2-hc9c-229v

netfilter: nft_ct: bail out on template ct in get eval

Published Jun 25, 2026 · Updated Oct 30, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: kernel Package: linux Package: linux Package: linux-allwinner-5.19 Package: linux-aws Package: linux-aws-5.0 Package: linux-aws-5.11 Package: linux-aws-5.13 Package: linux-aws-5.15 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.4 Package: linux-aws-5.8 Package: linux-aws-6.14 Package: linux-aws-6.17 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-6.8 Package: linux-aws-7.0 Package: linux-aws-fips Package: linux-aws-hwe Package: linux-azure Package: linux-azure-4.15 Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.15 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.4 Package: linux-azure-5.8 Package: linux-azure-6.11 Package: linux-azure-6.14 Package: linux-azure-6.17 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-6.8 Package: linux-azure-7.0 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.15 Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.14 Package: linux-azure-fde-6.17 Package: linux-azure-fde-6.2 Package: linux-azure-fde-6.8 Package: linux-azure-fde-7.0 Package: linux-azure-fips Package: linux-azure-nvidia Package: linux-azure-nvidia-6.14 Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-4.15 Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.15 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.4 Package: linux-gcp-5.8 Package: linux-gcp-6.11 Package: linux-gcp-6.14 Package: linux-gcp-6.17 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-6.8 Package: linux-gcp-7.0 Package: linux-gcp-fips Package: linux-gke Package: linux-gke-4.15 Package: linux-gke-5.15 Package: linux-gke-5.4 Package: linux-gkeop Package: linux-gkeop-5.15 Package: linux-gkeop-5.4 Package: linux-hwe Package: linux-hwe-5.11 Package: linux-hwe-5.13 Package: linux-hwe-5.15 Package: linux-hwe-5.19 Package: linux-hwe-5.4 Package: linux-hwe-5.8 Package: linux-hwe-6.11 Package: linux-hwe-6.14 Package: linux-hwe-6.17 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-6.8 Package: linux-hwe-7.0 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-5.15 Package: linux-ibm-5.4 Package: linux-ibm-6.8 Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-intel-iotg Package: linux-intel-iotg-5.15 Package: linux-iot Package: linux-kvm Package: linux-lowlatency Package: linux-lowlatency-hwe-5.15 Package: linux-lowlatency-hwe-5.19 Package: linux-lowlatency-hwe-6.11 Package: linux-lowlatency-hwe-6.2 Package: linux-lowlatency-hwe-6.5 Package: linux-lowlatency-hwe-6.8 Package: linux-lts-xenial Package: linux-nvidia Package: linux-nvidia-6.11 Package: linux-nvidia-6.17 Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-6.8 Package: linux-nvidia-7.0 Package: linux-nvidia-bos Package: linux-nvidia-lowlatency Package: linux-nvidia-tegra Package: linux-nvidia-tegra-5.15 Package: linux-nvidia-tegra-igx Package: linux-oem Package: linux-oem-5.10 Package: linux-oem-5.13 Package: linux-oem-5.14 Package: linux-oem-5.17 Package: linux-oem-5.6 Package: linux-oem-6.0 Package: linux-oem-6.1 Package: linux-oem-6.11 Package: linux-oem-6.14 Package: linux-oem-6.17 Package: linux-oem-6.5 Package: linux-oem-6.8 Package: linux-oem-7.0 Package: linux-oracle Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.15 Package: linux-oracle-5.3 Package: linux-oracle-5.4 Package: linux-oracle-5.8 Package: linux-oracle-6.14 Package: linux-oracle-6.17 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-oracle-7.0 Package: linux-raspi Package: linux-raspi-5.4 Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.14 Package: linux-realtime-6.17 Package: linux-realtime-6.8 Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.15 Package: linux-riscv-5.19 Package: linux-riscv-5.8 Package: linux-riscv-6.14 Package: linux-riscv-6.17 Package: linux-riscv-6.5 Package: linux-riscv-6.8 Package: linux-riscv-7.0 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Package: linux-vmware Package: linux-xilinx Package: linux-xilinx-zynqmp Platform: Linux Ecosystem: Azure Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

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

netfilter: nft_ct: bail out on template ct in get eval

I noticed this issue while looking at a historic syzbot report [1].

A rule like the one below is enough to trigger the bug:

table ip t {
chain pre {
type filter hook prerouting priority raw;
ct zone set 1
ct original saddr 1.2.3.4 accept
}
}

The first expression attaches a per-cpu template ct via
nft_ct_set_zone_eval() (nf_ct_tmpl_alloc -> kzalloc, tuple is all
zero, nf_ct_l3num(ct) == 0). The next expression then calls
nft_ct_get_eval() on the same skb, treats the template as a real ct
and hits the 16-byte memcpy path. With dreg at NFT_REG32_15 this
overflows past struct nft_regs on the kernel stack; with smaller
dreg values it silently clobbers adjacent registers.

Reject template ct at the eval entry and in nft_ct_get_fast_eval(),
mirroring the check nft_ct_set_eval() already has. Additionally,
bound the address copy in NFT_CT_SRC / NFT_CT_DST by priv->len
instead of by nf_ct_l3num(ct): nf_ct_get_tuple() zeroes the tuple
before pkt_to_tuple() fills in only the protocol-relevant leading
bytes, so the trailing bytes of tuple->{src,dst}.u3.all are
well-defined zero. priv->len is validated at rule load, so the
copy size is now bounded by the destination register rather than
by an untrusted field on the conntrack.

[1]: https://syzkaller.appspot.com/bug?id=389cf09cb72926114fce90dc85a2c3231dcb647c

Affected products

VendorProductAffectedFixed
Linux Linux 4.1 6.1.191

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.

ReleasePackageFixed inAdvisory
Debian 14 linux 7.0.13-1 —
Debian 13 linux 6.12.94-1 —
Debian 12 linux No fix yet —
ReleasePackageFixed inAdvisory
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 26.04 LTS linux 7.0.0-31.31 USN-8726-1
Ubuntu 26.04 LTS linux-aws 7.0.0-1012.12 USN-8726-1
Ubuntu 26.04 LTS linux-azure 7.0.0-1014.14 USN-8726-4
Ubuntu 26.04 LTS linux-gcp +1 7.0.0-1011.11 USN-8726-4, USN-8726-1
Ubuntu 26.04 LTS linux-gke 7.0.0-1006.7 USN-8726-1
Ubuntu 26.04 LTS linux-ibm +2 7.0.0-1013.13 USN-8727-1, USN-8726-3
Ubuntu 26.04 LTS linux-nvidia 7.0.0-1018.18 USN-8760-2
Ubuntu 26.04 LTS linux-nvidia-bos 7.0.0-2018.18 USN-8800-1
Ubuntu 26.04 LTS linux-raspi 7.0.0-1019.19 USN-8726-2
Ubuntu 26.04 LTS linux-riscv +1 7.0.0-31.31.1 USN-8726-1
Ubuntu 25.10 linux +8 No fix yet —
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-7.0 7.0.0-1012.12~24.04.1 USN-8726-1
Ubuntu 24.04 LTS linux-azure-7.0 7.0.0-1014.14~24.04.1 USN-8728-2
Ubuntu 24.04 LTS linux-azure-fde 6.8.0-1068.75 USN-8904-1
Ubuntu 24.04 LTS linux-azure-fde-7.0 7.0.0-1013.13~24.04.1 —
Ubuntu 24.04 LTS linux-gcp +1 6.8.0-1070.78 USN-8905-2, USN-8904-1
Ubuntu 24.04 LTS linux-gcp-7.0 +1 7.0.0-1011.11~24.04.1 USN-8728-3, USN-8728-1
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-7.0 7.0.0-31.31~24.04.1 USN-8726-1
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-7.0 7.0.0-1018.18~24.04.1 USN-8760-1
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1064.67.1 USN-8903-2
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1036.39 USN-8886-1
Ubuntu 24.04 LTS linux-oracle 6.8.0-1063.66 USN-8903-2
Ubuntu 24.04 LTS linux-raspi 6.8.0-1068.72 USN-9025-1
Ubuntu 24.04 LTS linux-riscv +29 No fix yet —
Ubuntu 24.04 LTS linux-riscv-7.0 7.0.0-31.31.1~24.04.1 —
Ubuntu 24.04 LTS linux-vmware 6.8.0-1008.8 —
Show 19 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
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 —
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 +1 No fix yet —
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 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 16.04 LTS linux-fips 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-updates 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-updates 16.04 LTS linux-fips 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 +12 No fix yet —
Ubuntu Pro 16.04 LTS linux +7 No fix yet —
Ubuntu Pro 14.04 LTS linux-aws +2 No fix yet —
ReleasePackageFixed inAdvisory
SLES 15 SP7 kernel-64kb +7 6.4.0-150700.53.78.1 SUSE-SU-2026:3790-1
SLES 15 SP7 kernel-default-base 6.4.0-150700.53.78.1.150700.17.43.2 SUSE-SU-2026:3790-1
SLES 15 SP6 kernel-64kb +6 6.4.0-150600.23.130.1 SUSE-SU-2026:3602-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.130.1.150600.12.60.3 SUSE-SU-2026:3602-1
SLES 15 SP5 kernel-64kb +6 5.14.21-150500.55.182.1 SUSE-SU-2026:3595-1
SLES 15 SP5 kernel-default-base 5.14.21-150500.55.182.1.150500.6.85.2 SUSE-SU-2026:3595-1
SLES 15 SP4 kernel-64kb +6 5.14.21-150400.24.235.1 SUSE-SU-2026:3593-1
SLES 15 SP4 kernel-default-base 5.14.21-150400.24.235.1.150400.24.118.3 SUSE-SU-2026:3593-1
SLES 12 SP5 kernel-syms +2 4.12.14-122.323.1 SUSE-SU-2026:3594-1
Show 19 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 16.0 kernel-64kb +8 6.12.0-160000.37.1 SUSE-SU-2026:23231-1, SUSE-SU-2026:23221-1
SLES for SAP 16.0 kernel-default-base 6.12.0-160000.37.1.160000.2.19 SUSE-SU-2026:23231-1, SUSE-SU-2026:23221-1
SLES for SAP 15 SP6 kernel-default-base 6.4.0-150600.23.130.1.150600.12.60.3 SUSE-SU-2026:3602-1
SLES for SAP 15 SP6 kernel-docs +4 6.4.0-150600.23.130.1 SUSE-SU-2026:3602-1
SLES for SAP 15 SP5 kernel-default-base 5.14.21-150500.55.182.1.150500.6.85.2 SUSE-SU-2026:3595-1
SLES for SAP 15 SP5 kernel-docs +4 5.14.21-150500.55.182.1 SUSE-SU-2026:3595-1
SLES for SAP 15 SP4 kernel-default-base 5.14.21-150400.24.235.1.150400.24.118.3 SUSE-SU-2026:3593-1
SLES for SAP 15 SP4 kernel-docs +4 5.14.21-150400.24.235.1 SUSE-SU-2026:3593-1
SLES 16.0 kernel-64kb +8 6.12.0-160000.37.1 SUSE-SU-2026:23237-1, SUSE-SU-2026:23231-1, SUSE-SU-2026:23221-1
SLES 16.0 kernel-default-base 6.12.0-160000.37.1.160000.2.19 SUSE-SU-2026:23231-1, SUSE-SU-2026:23221-1
SLE Micro 6.2 kernel-default-base 6.12.0-160000.37.1.160000.2.19 SUSE-SU-2026:23068-1
SLE Micro 6.2 kernel-rt +5 6.12.0-160000.37.1 SUSE-SU-2026:23068-1, SUSE-SU-2026:23066-1
SLE Micro 6.1 kernel-rt +4 6.4.0-51.1 SUSE-SU-2026:23194-1, SUSE-SU-2026:23193-1
SLE Micro 6.0 kernel-rt +4 6.4.0-51.1 SUSE-SU-2026:23244-1, SUSE-SU-2026:23241-1
SLE Micro 5.5 kernel-default-base 5.14.21-150500.55.182.1.150500.6.85.2 SUSE-SU-2026:3595-1
SLE Micro 5.5 kernel-rt +1 5.14.21-150500.13.156.1 SUSE-SU-2026:3617-1
SLE Micro 5.5 kernel-source +1 5.14.21-150500.55.182.1 SUSE-SU-2026:3595-1
SLE Micro 5.4 kernel-default-base 5.14.21-150400.24.235.1.150400.24.118.3 SUSE-SU-2026:3593-1
SLE Micro 5.4 kernel-rt +1 5.14.21-150400.15.181.1 SUSE-SU-2026:3616-1
SLE Micro 5.4 kernel-source +1 5.14.21-150400.24.235.1 SUSE-SU-2026:3593-1
SLE Micro 5.3 kernel-default-base 5.14.21-150400.24.235.1.150400.24.118.3 SUSE-SU-2026:3593-1
SLE Micro 5.3 kernel-rt +1 5.14.21-150400.15.181.1 SUSE-SU-2026:3616-1
SLE Micro 5.3 kernel-source +1 5.14.21-150400.24.235.1 SUSE-SU-2026:3593-1
SLE Live Patching 15 SP7 kernel-default 6.4.0-150700.53.78.1 SUSE-SU-2026:3790-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7-RT_Update_19 1-150700.1.5.1 SUSE-SU-2026:3810-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_20 1-150700.15.3.2 SUSE-SU-2026:3790-1
SLE Live Patching 15 SP6 kernel-default 6.4.0-150600.23.130.1 SUSE-SU-2026:3602-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_30 1-150600.13.5.1 SUSE-SU-2026:3602-1
SLE Live Patching 15 SP5 kernel-default 5.14.21-150500.55.182.1 SUSE-SU-2026:3595-1
SLE Live Patching 15 SP5 kernel-livepatch-SLE15-SP5_Update_44 1-150500.11.5.1 SUSE-SU-2026:3595-1
SLE Live Patching 15 SP4 kernel-default 5.14.21-150400.24.235.1 SUSE-SU-2026:3593-1
SLE Live Patching 15 SP4 kernel-livepatch-SLE15-SP4_Update_58 1-150400.9.7.1 SUSE-SU-2026:3593-1
SLE Live Patching 12 SP5 kernel-default 4.12.14-122.323.1 SUSE-SU-2026:3594-1
SLE Live Patching 12 SP5 kgraft-patch-SLE12-SP5_Update_86 1-8.3.1 SUSE-SU-2026:3594-1
SLE HPC 15 SP5 kernel-64kb +5 5.14.21-150500.55.182.1 SUSE-SU-2026:3595-1
SLE HPC 15 SP5 kernel-default-base 5.14.21-150500.55.182.1.150500.6.85.2 SUSE-SU-2026:3595-1
SLE HPC 15 SP4 kernel-64kb +5 5.14.21-150400.24.235.1 SUSE-SU-2026:3593-1
SLE HPC 15 SP4 kernel-default-base 5.14.21-150400.24.235.1.150400.24.118.3 SUSE-SU-2026:3593-1
SUSE Real Time Module 15 SP7 kernel-rt +2 6.4.0-150700.7.72.1 SUSE-SU-2026:3810-1
ReleasePackageFixed inAdvisory
openSUSE Leap 16.0 kernel-default-base 6.12.0-160000.37.1.160000.2.19 openSUSE-SU-2026:21555-1
openSUSE Leap 16.0 kernel-rt +11 6.12.0-160000.37.1 openSUSE-SU-2026:21555-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 kernel-livepatch-6.18.36-69.134 +1 1:1.0-0.amzn2023 ALAS2023-2026-1968, ALAS2023-2026-1925
Amazon Linux 2023 perf6.12 +11 1:6.12.94-123.174.amzn2023 ALAS2023-2026-1968
Amazon Linux 2023 perf6.18 +12 1:6.18.36-69.134.amzn2023 ALAS2023-2026-1925

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 kernel 6.6.143.1-1 —

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 9 kernel-uek +34 6.12.0-206.104.3.3.el10uek ELSA-2026-500248

Advisories 42

References