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Vulnerability · Published Sep 4, 2026 · Assigned by Linux

CVE-2026-80793ipv4: reject undersized MTUs in ip_do_fragment()

Unrated

In plain English

A 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 0.2% (higher than 9% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS )–Not rated
Exploit odds (30 days)0.2%top 90.7% 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: ipv4: reject undersized MTUs in ip_do_fragment() ip_do_fragment() subtracts the IPv4 header length from the effective MTU and passes the resulting payload MTU to ip_frag_next(). If the effective MTU is smaller than hlen + 8, ip_frag_next() rounds the fragment payload length down to zero. The fragmentation state then never makes forward progress: state->left, state->ptr and state->offset stay unchanged while ip_do_fragment() keeps allocating and transmitting header-only fragments until the softlockup detector fires. This is reproducible with a route installed using "mtu lock 20", but it is also reproducible without route MTU lock, for example by forwarding a packet to a device whose MTU is 20. Fix it in ip_do_fragment() by rejecting mtu < hlen + 8 with -EMSGSIZE, matching the existing IPv6 fragmentation check.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.187-1DEBIAN-CVE-2026-80793
Debian:13linux6.12.107-1DEBIAN-CVE-2026-80793
Debian:14linux7.1.12-1DEBIAN-CVE-2026-80793
Debian:12linux-6.126.12.107-1~deb12u1DEBIAN-CVE-2026-80793
Ubuntu:22.04:LTSlinux5.15.0-202.212UBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinuxno fix listedUBUNTU-CVE-2026-80793
Ubuntu:26.04:LTSlinux7.0.0-42.42UBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-aws5.15.0-1119.126UBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-awsno fix listedUBUNTU-CVE-2026-80793
Ubuntu:26.04:LTSlinux-aws7.0.0-1016.17UBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-aws-6.8no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-aws-7.0no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-azure5.15.0-1125.134UBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-80793
Ubuntu:26.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-azure-6.8no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-azure-7.0no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1124.133UBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-80793
Ubuntu:26.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-azure-fde-6.8no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-azure-fde-7.0no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-gcp5.15.0-1120.130UBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2026-80793
Ubuntu:26.04:LTSlinux-gcp7.0.0-1016.18UBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-gcp-6.8no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-gcp-7.0no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-gke5.15.0-1115.121UBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-80793
Ubuntu:26.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1102.110UBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-gkeopno fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-hwe-6.8no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-42.42~24.04.1UBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-ibm5.15.0-1113.117UBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-ibmno fix listedUBUNTU-CVE-2026-80793
Ubuntu:26.04:LTSlinux-ibm7.0.0-1017.17UBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-ibm-6.8no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1114.120UBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-kvm5.15.0-1111.116UBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-197.207UBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-lowlatencyno fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.8no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1114.115UBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-80793
Ubuntu:26.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-nvidia-6.8no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-nvidia-7.0no fix listedUBUNTU-CVE-2026-80793
Ubuntu:26.04:LTSlinux-nvidia-bosno fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-nvidia-lowlatencyno fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1070.72UBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-nvidia-tegrano fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1059.59UBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-80793
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1017.17UBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-oracle5.15.0-1116.122UBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-oracleno fix listedUBUNTU-CVE-2026-80793
Ubuntu:26.04:LTSlinux-oracle7.0.0-1015.16UBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-oracle-6.8no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-oracle-7.0no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-80793
Ubuntu:26.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-80793
Ubuntu:26.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-80793
Ubuntu:26.04:LTSlinux-riscv7.0.0-42.42.1UBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-riscv-6.8no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-riscv-7.07.0.0-42.42.1~24.04.1UBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-vmwareno fix listedUBUNTU-CVE-2026-80793
Ubuntu:24.04:LTSlinux-xilinxno fix listedUBUNTU-CVE-2026-80793
Ubuntu:22.04:LTSlinux-xilinx-zynqmpno fix listedUBUNTU-CVE-2026-80793

Affected products (as reported)

VendorProductVersions
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before a716a64a4ba68cd46f2745fba2b1099fe8e0aa591da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 515b6816ba0c12d8415c88e5f41e6ec029e35cfa1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 74ce7389f8f562d39015f59a00ef7ad6acd378031da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before b0ea911453ce7210e8200a07a94d2458bd1e64301da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 36e0741833bd823866f8cb9f112f37cea1a70b601da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before d9d1a676b033acabf8e5645f730486d1f8204a3f1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 3556beb8ca86677af2aca5bfbed6f8e790fccc831da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before c8a74adccaf028223054633b532593101dfcc581
Linux Linux 2.6.12

References