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Vulnerability · Published Mar 18, 2026 · Assigned by Linux

CVE-2026-23254net: gro: fix outer network offset

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 98.1% 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: net: gro: fix outer network offset The udp GRO complete stage assumes that all the packets inserted the RX have the `encapsulation` flag zeroed. Such assumption is not true, as a few H/W NICs can set such flag when H/W offloading the checksum for an UDP encapsulated traffic, the tun driver can inject GSO packets with UDP encapsulation and the problematic layout can also be created via a veth based setup. Due to the above, in the problematic scenarios, udp4_gro_complete() uses the wrong network offset (inner instead of outer) to compute the outer UDP header pseudo checksum, leading to csum validation errors later on in packet processing. Address the issue always clearing the encapsulation flag at GRO completion time. Such flag will be set again as needed for encapsulated packets by udp_gro_complete().

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13linux6.12.73-1DEBIAN-CVE-2026-23254
Debian:14linux6.18.10-1DEBIAN-CVE-2026-23254
Ubuntu:24.04:LTSlinux6.8.0-117.117UBUNTU-CVE-2026-23254
Ubuntu:25.10linuxno fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-aws6.8.0-1055.58UBUNTU-CVE-2026-23254
Ubuntu:25.10linux-awsno fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1057.60~22.04.1UBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-azure6.8.0-1056.62UBUNTU-CVE-2026-23254
Ubuntu:25.10linux-azureno fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1059.65~22.04.1UBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1058.65UBUNTU-CVE-2026-23254
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1058.65~22.04.1UBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-gcp6.8.0-1058.61UBUNTU-CVE-2026-23254
Ubuntu:25.10linux-gcpno fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1060.63~22.04.1UBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-gke6.8.0-1054.60UBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1041.44UBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-124.124~22.04.1UBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-ibm6.8.0-1055.56UBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1055.56~22.04.1UBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-117.117.1UBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-117.117.1~22.04.1UBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1054.57UBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1054.57~22.04.1UBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1054.57.1UBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1024.24UBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-oracle6.8.0-1054.55UBUNTU-CVE-2026-23254
Ubuntu:25.10linux-oracleno fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1054.55~22.04.1UBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-raspi6.8.0-1056.60UBUNTU-CVE-2026-23254
Ubuntu:25.10linux-raspino fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-23254
Ubuntu:25.10linux-realtimeno fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-23254
Ubuntu:25.10linux-riscvno fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-117.117~22.04.1UBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-23254
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-23254
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1032.33UBUNTU-CVE-2026-23254

Affected products (as reported)

VendorProductVersions
Linux Linux af276a5ac8e938c8b058e3e124073cc1e322d98b – before 9d40a85138568696387ef04cd004c64612a708745ef31ea5d053a8f493a772ebad3f3ce82c35d845 – before b83557bc6f560433fe5d727e241069f8db5ba7095ef31ea5d053a8f493a772ebad3f3ce82c35d845 – before 2e5edb69e5d0e23ef248c56fc977039268c77a7b5ef31ea5d053a8f493a772ebad3f3ce82c35d845 – before 5c2c3c38be396257a6a2e55bd601a12bb9781507dbd9466d323a72e22efe09151253d195d36d3bf66.6.31 – before 6.6.1246.8.10 – before 6.9
Linux Linux 6.9

References