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Vulnerability · Published Jun 25, 2026 · Assigned by Linux

CVE-2026-53221ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()

Critical 9.8

In plain English

A critical-severity improper input validation 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 0.6% (higher than 48% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.6%top 52.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup() In vti6_tnl_lookup(), when an exact match for a tunnel fails, the code falls back to searching for wildcard tunnels: - Tunnels matching the packet's local address, with any remote address wildcard remote). - Tunnels matching the packet's remote address, with any local address (wildcard local). However, vti6 stores all these different types of tunnels in the same hash table (ip6n->tnls_r_l) prone to hash collisions. The bug is that the fallback search loops in vti6_tnl_lookup() were missing checks to ensure that the candidate tunnel actually has a wildcard address.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.176-1DEBIAN-CVE-2026-53221
Debian:13linux6.12.94-1DEBIAN-CVE-2026-53221
Debian:14linux7.0.13-1DEBIAN-CVE-2026-53221
Ubuntu:22.04:LTSlinux5.15.0-194.204USN-8818-4
Ubuntu:22.04:LTSlinux5.15.0-194.204UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux6.8.0-142.142UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux6.8.0-142.142USN-8817-1
Ubuntu:25.10linuxno fix listedUBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux7.0.0-29.29UBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux7.0.0-29.29USN-8629-1
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-aws5.15.0-1116.123USN-8818-1
Ubuntu:22.04:LTSlinux-aws5.15.0-1116.123UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-aws6.8.0-1065.68UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-aws6.8.0-1065.68USN-8817-3
Ubuntu:25.10linux-awsno fix listedUBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-aws7.0.0-1010.10USN-8629-1
Ubuntu:26.04:LTSlinux-aws7.0.0-1010.10UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1065.68~22.04.1USN-8817-3
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1065.68~22.04.1UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-aws-7.07.0.0-1010.10~24.04.1UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-aws-7.07.0.0-1010.10~24.04.1USN-8629-2
Ubuntu:22.04:LTSlinux-azure5.15.0-1122.131UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-azure5.15.0-1122.131USN-8818-1
Ubuntu:24.04:LTSlinux-azure6.8.0-1068.76USN-8817-1
Ubuntu:24.04:LTSlinux-azure6.8.0-1068.76UBUNTU-CVE-2026-53221
Ubuntu:25.10linux-azureno fix listedUBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-azure7.0.0-1011.11UBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-azure7.0.0-1011.11USN-8629-1
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1068.76~22.04.1USN-8817-1
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1068.76~22.04.1UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-azure-7.07.0.0-1014.14~24.04.1UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1121.130UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1121.130USN-8818-1
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1066.73UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1066.73USN-8817-1
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1010.10UBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1010.10USN-8629-1
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1066.73~22.04.1USN-8817-1
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1066.73~22.04.1UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-azure-fde-7.07.0.0-1013.13~24.04.1UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-gcp5.15.0-1117.127UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-gcp5.15.0-1117.127USN-8818-1
Ubuntu:24.04:LTSlinux-gcp6.8.0-1069.77UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-gcp6.8.0-1069.77USN-8817-1
Ubuntu:25.10linux-gcpno fix listedUBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-gcp7.0.0-1010.10USN-8660-1
Ubuntu:26.04:LTSlinux-gcp7.0.0-1010.10UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1069.77~22.04.1USN-8817-1
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1069.77~22.04.1UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-gcp-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-gke5.15.0-1112.118USN-8818-1
Ubuntu:22.04:LTSlinux-gke5.15.0-1112.118UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-gke6.8.0-1064.72USN-8817-1
Ubuntu:24.04:LTSlinux-gke6.8.0-1064.72UBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-gke7.0.0-1005.6USN-8660-1
Ubuntu:26.04:LTSlinux-gke7.0.0-1005.6UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1099.107UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1099.107USN-8818-1
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1050.54UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1050.54USN-8817-1
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-hwe-6.8no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-29.29~24.04.2USN-8629-3
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-29.29~24.04.2UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-ibm5.15.0-1110.114UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-ibm5.15.0-1110.114USN-8818-1
Ubuntu:24.04:LTSlinux-ibm6.8.0-1065.66USN-8817-1
Ubuntu:24.04:LTSlinux-ibm6.8.0-1065.66UBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-ibm7.0.0-1011.11USN-8629-1
Ubuntu:26.04:LTSlinux-ibm7.0.0-1011.11UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1066.67~22.04.1UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1111.117UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1111.117USN-8818-1
Ubuntu:22.04:LTSlinux-kvm5.15.0-1108.113UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-kvm5.15.0-1108.113USN-8818-1
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-194.204UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-194.204USN-8818-1
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-142.142.1USN-8817-1
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-142.142.1UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-142.142.1~22.04.1USN-8817-1
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-142.142.1~22.04.1UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1111.112UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1111.112USN-8818-4
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1063.66USN-8842-1
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1063.66UBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-nvidia7.0.0-1016.16UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1063.66~22.04.1UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1063.66~22.04.1USN-8842-1
Ubuntu:24.04:LTSlinux-nvidia-7.07.0.0-1016.16~24.04.1UBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-nvidia-bos7.0.0-2016.16UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1063.66.1UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1063.66.1USN-8842-1
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1068.70UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1068.70USN-8818-5
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1035.38UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1057.57USN-8818-5
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1057.57UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1010.10UBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1010.10USN-8637-1
Ubuntu:22.04:LTSlinux-oracle5.15.0-1113.119USN-8818-1
Ubuntu:22.04:LTSlinux-oracle5.15.0-1113.119UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-oracle6.8.0-1062.65USN-8817-1
Ubuntu:24.04:LTSlinux-oracle6.8.0-1062.65UBUNTU-CVE-2026-53221
Ubuntu:25.10linux-oracleno fix listedUBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-oracle7.0.0-1009.9UBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-oracle7.0.0-1009.9USN-8629-1
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1062.65~22.04.1UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1062.65~22.04.1USN-8817-1
Ubuntu:24.04:LTSlinux-oracle-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-raspi5.15.0-1110.113UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-raspi5.15.0-1110.113USN-8871-1
Ubuntu:24.04:LTSlinux-raspi6.8.0-1065.69UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-raspi6.8.0-1065.69USN-8817-1
Ubuntu:25.10linux-raspino fix listedUBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-raspi7.0.0-1016.16USN-8629-1
Ubuntu:26.04:LTSlinux-raspi7.0.0-1016.16UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-53221
Ubuntu:25.10linux-realtimeno fix listedUBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-realtime7.0.0-29.29.1UBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-realtime7.0.0-29.29.1USN-8629-1
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-53221
Ubuntu:25.10linux-riscvno fix listedUBUNTU-CVE-2026-53221
Ubuntu:26.04:LTSlinux-riscv7.0.0-29.29.1UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-142.142~22.04.1UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-riscv-7.07.0.0-30.30.1~24.04.1UBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-vmware6.8.0-1008.8UBUNTU-CVE-2026-53221
Ubuntu:24.04:LTSlinux-xilinxno fix listedUBUNTU-CVE-2026-53221
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1079.83USN-8818-1
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1079.83UBUNTU-CVE-2026-53221

Affected products (as reported)

VendorProductVersions
Linux Linux fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 – before c327fa4fca31415431202e063767a7ae342e19c6fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 – before fc657ac0767c49839b3ef0b08dc0953ca30883f8fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 – before 47fb3c2b4203556308e64354b3e78f2ce221d646fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 – before f513f308cc4bdb4530d033431592ffbc29b7fca1fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 – before 90fd4513315ca07da99cfd8549d3e553a7160f0dfbe68ee87522f6eaa10f9076c0a7117e1613f2f7 – before 2abfb19bbb81958714ad1d43ebeb65b30394184bfbe68ee87522f6eaa10f9076c0a7117e1613f2f7 – before 2fc7bc087cc7085368263d9d37bfe9a0bddd6a2dfbe68ee87522f6eaa10f9076c0a7117e1613f2f7 – before a5c0359f5cbc51a2e2b114d6041e0f3c73f903e9
Linux Linux 3.19

Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References