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Vulnerability · Published Jun 25, 2026 · Assigned by Linux

CVE-2026-53269netfilter: synproxy: add mutex to guard hook reference counting

Medium 5.5

In plain English

A medium-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.1%top 98.2% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: netfilter: synproxy: add mutex to guard hook reference counting As the synproxy infrastructure register netfilter hooks on-demand when a user adds the first iptables target or nftables expression, if done concurrently they can race each other. Introduce a mutex to serialize the refcount control blocks access from both frontends. While a per namespace mutex might be more efficient, it is not needed for target/expression like SYNPROXY.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.176-1DEBIAN-CVE-2026-53269
Debian:13linux6.12.94-1DEBIAN-CVE-2026-53269
Debian:14linux7.0.13-1DEBIAN-CVE-2026-53269
Ubuntu:22.04:LTSlinux5.15.0-198.208UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux6.8.0-146.146UBUNTU-CVE-2026-53269
Ubuntu:25.10linuxno fix listedUBUNTU-CVE-2026-53269
Ubuntu:26.04:LTSlinux7.0.0-31.31UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-aws5.15.0-1117.124UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-aws6.8.0-1066.69UBUNTU-CVE-2026-53269
Ubuntu:25.10linux-awsno fix listedUBUNTU-CVE-2026-53269
Ubuntu:26.04:LTSlinux-aws7.0.0-1012.12UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1066.69~22.04.1UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-aws-7.07.0.0-1012.12~24.04.1UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-azure5.15.0-1123.132UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-azure6.8.0-1070.78UBUNTU-CVE-2026-53269
Ubuntu:25.10linux-azureno fix listedUBUNTU-CVE-2026-53269
Ubuntu:26.04:LTSlinux-azure7.0.0-1014.14UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1070.78~22.04.1UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-azure-7.07.0.0-1014.14~24.04.1UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1122.131UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1068.75UBUNTU-CVE-2026-53269
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2026-53269
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1013.13UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1068.75~22.04.1UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-azure-fde-7.07.0.0-1013.13~24.04.1UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-gcp5.15.0-1118.128UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-gcp6.8.0-1070.78UBUNTU-CVE-2026-53269
Ubuntu:25.10linux-gcpno fix listedUBUNTU-CVE-2026-53269
Ubuntu:26.04:LTSlinux-gcp7.0.0-1011.11UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1070.78~22.04.1UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-gcp-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-gke5.15.0-1113.119UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-gke6.8.0-1065.73UBUNTU-CVE-2026-53269
Ubuntu:26.04:LTSlinux-gke7.0.0-1006.7UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1100.108UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1051.55UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-hwe-6.8no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-31.31~24.04.1UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-ibm5.15.0-1111.115UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-ibm6.8.0-1066.67UBUNTU-CVE-2026-53269
Ubuntu:26.04:LTSlinux-ibm7.0.0-1013.13UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1066.67~22.04.1UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1112.118UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-kvm5.15.0-1109.114UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-195.205UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-146.146.1UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-146.146.1~22.04.1UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1112.113UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1064.67UBUNTU-CVE-2026-53269
Ubuntu:26.04:LTSlinux-nvidia7.0.0-1018.18UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1064.67~22.04.1UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-nvidia-7.07.0.0-1018.18~24.04.1UBUNTU-CVE-2026-53269
Ubuntu:26.04:LTSlinux-nvidia-bos7.0.0-2018.18UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1064.67.1UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1070.72UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1035.38UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1059.59UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-53269
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1013.13UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-oracle5.15.0-1114.120UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-oracle6.8.0-1063.66UBUNTU-CVE-2026-53269
Ubuntu:25.10linux-oracleno fix listedUBUNTU-CVE-2026-53269
Ubuntu:26.04:LTSlinux-oracle7.0.0-1011.11UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-oracle-6.8no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-oracle-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-53269
Ubuntu:25.10linux-raspino fix listedUBUNTU-CVE-2026-53269
Ubuntu:26.04:LTSlinux-raspi7.0.0-1019.19UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-53269
Ubuntu:25.10linux-realtimeno fix listedUBUNTU-CVE-2026-53269
Ubuntu:26.04:LTSlinux-realtime7.0.0-31.31.1UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-53269
Ubuntu:25.10linux-riscvno fix listedUBUNTU-CVE-2026-53269
Ubuntu:26.04:LTSlinux-riscv7.0.0-31.31.1UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-146.146~22.04.1UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-riscv-7.07.0.0-31.31.1~24.04.1UBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-vmware6.8.0-1008.8UBUNTU-CVE-2026-53269
Ubuntu:24.04:LTSlinux-xilinxno fix listedUBUNTU-CVE-2026-53269
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1080.84UBUNTU-CVE-2026-53269

Affected products (as reported)

VendorProductVersions
Linux Linux ad49d86e07a497e834cb06f2b151dccd75f8e148 – before 0ec9ddc1bda261a2c57636c74c8b4e53000102c9ad49d86e07a497e834cb06f2b151dccd75f8e148 – before 56ffbe3a08c01dcdb0d6adee9ce1e535bfb3b389ad49d86e07a497e834cb06f2b151dccd75f8e148 – before debc57b83d5b323df74bf010c8d50fe26ad2ed6bad49d86e07a497e834cb06f2b151dccd75f8e148 – before 0f8ba5e4c53d2e4a536aa68140beda9fe59b2f88ad49d86e07a497e834cb06f2b151dccd75f8e148 – before 640441348258220e78daed40528b85b8afcedab6ad49d86e07a497e834cb06f2b151dccd75f8e148 – before aaf80701dc2f7a48fe543961e21f8ca3924d587cad49d86e07a497e834cb06f2b151dccd75f8e148 – before fbf0591275f50eae5733c3d7a8cd6c1e79933ffaad49d86e07a497e834cb06f2b151dccd75f8e148 – before 2fcba19caaeb2a33017459d3430f057967bb91b6
Linux Linux 5.3

References