{"id":"CVE-2026-68123","title":"openvswitch: fix GSO userspace truncation underflow","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nopenvswitch: fix GSO userspace truncation underflow\n\nOVS_ACTION_ATTR_TRUNC currently stores a delta from the original skb\nlength in OVS_CB(skb)->cutlen. When a later us…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < 50a6a85f3d6b1d22d8436848606cdef5d2c490b4","Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < 2623c48cc3a8da9a1886fd8f65c0e348f4406fd6","Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < e211b081901ffca76674082c73eeaed53524c369","Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855","Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc","Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < 100a23b1613e9218e0af654ef102352c713f0263","Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < ea85dbcbe8d4056ecb54352f97743d138ea4c407","Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < 4032f8ed10fcb84d41c508dfb04be96589f78dfe","Linux 4.8"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-16T15:44:13.520896Z"},"published":"2026-08-10","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:52:57.977Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-68123","references":[{"url":"https://git.kernel.org/stable/c/50a6a85f3d6b1d22d8436848606cdef5d2c490b4"},{"url":"https://git.kernel.org/stable/c/2623c48cc3a8da9a1886fd8f65c0e348f4406fd6"},{"url":"https://git.kernel.org/stable/c/e211b081901ffca76674082c73eeaed53524c369"},{"url":"https://git.kernel.org/stable/c/a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855"},{"url":"https://git.kernel.org/stable/c/fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc"},{"url":"https://git.kernel.org/stable/c/100a23b1613e9218e0af654ef102352c713f0263"},{"url":"https://git.kernel.org/stable/c/ea85dbcbe8d4056ecb54352f97743d138ea4c407"},{"url":"https://git.kernel.org/stable/c/4032f8ed10fcb84d41c508dfb04be96589f78dfe"}],"tags":["cve.org"],"epss":0.00552,"epssPercentile":0.44907,"ingestedAt":"2026-10-16T17:24:46.842Z","slug":"CVE-2026-68123","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nopenvswitch: fix GSO userspace truncation underflow\n\nOVS_ACTION_ATTR_TRUNC currently stores a delta from the original skb\nlength in OVS_CB(skb)->cutlen. When a later userspace action segments a\nGSO skb, queue_gso_packets() reuses that delta for each smaller segment.\nA segment can then reach queue_userspace_packet() with cutlen greater\nthan skb->len, underflowing the length passed to skb_zerocopy().\n\nStore the maximum preserved length instead and bound each consumer\nagainst the current skb length. Use U32_MAX as the no-truncation\nsentinel so the value remains valid if skb geometry changes before a\nconsumer handles it.\n\n## Affected\n\n- `Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < 50a6a85f3d6b1d22d8436848606cdef5d2c490b4`\n- `Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < 2623c48cc3a8da9a1886fd8f65c0e348f4406fd6`\n- `Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < e211b081901ffca76674082c73eeaed53524c369`\n- `Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855`\n- `Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc`\n- `Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < 100a23b1613e9218e0af654ef102352c713f0263`\n- `Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < ea85dbcbe8d4056ecb54352f97743d138ea4c407`\n- `Linux >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 < 4032f8ed10fcb84d41c508dfb04be96589f78dfe`\n- `Linux 4.8`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}