{"id":"CVE-2026-72405","title":"net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync\n\nYue Sun reported a use-after-free and debugobjects warning in\nudp_tunnel_nic_device_sync_work() …","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= cc4e3835eff474aa274d6e1d18f69d9d296d3b76 < cee6688e5731c0591643521716d1a1a5c1a98bf8","Linux >= cc4e3835eff474aa274d6e1d18f69d9d296d3b76 < 9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7","Linux >= cc4e3835eff474aa274d6e1d18f69d9d296d3b76 < 54292b167466cdf42176b7b6f01da66c184deb12","Linux >= cc4e3835eff474aa274d6e1d18f69d9d296d3b76 < ecf69d4b43370c587e48d4d70289dbdb7e039d4d","Linux 5.9"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T18:49:07.638343Z"},"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T18:55:21.945Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72405","references":[{"url":"https://git.kernel.org/stable/c/cee6688e5731c0591643521716d1a1a5c1a98bf8"},{"url":"https://git.kernel.org/stable/c/9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7"},{"url":"https://git.kernel.org/stable/c/54292b167466cdf42176b7b6f01da66c184deb12"},{"url":"https://git.kernel.org/stable/c/ecf69d4b43370c587e48d4d70289dbdb7e039d4d"}],"tags":["cve.org"],"epss":0.0017,"epssPercentile":0.05952,"ingestedAt":"2026-10-16T19:46:24.399Z","slug":"CVE-2026-72405","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync\n\nYue Sun reported a use-after-free and debugobjects warning in\nudp_tunnel_nic_device_sync_work() during concurrent device operations.\n\nThe workqueue core clears the internal pending bit before invoking the\nworker. At that point, a concurrent thread can queue the work again.\nWhen the already running worker eventually clears the work_pending flag\nto 0, it mistakenly clears the flag for the newly queued instance.\nudp_tunnel_nic_unregister() then observes work_pending as 0 and frees\nthe structure while the second work item is still active in the queue,\nleading to UAF.\n\nFix this by returning early in udp_tunnel_nic_device_sync() if\nwork_pending is already set, preventing redundant work queueing.\n\n## Affected\n\n- `Linux >= cc4e3835eff474aa274d6e1d18f69d9d296d3b76 < cee6688e5731c0591643521716d1a1a5c1a98bf8`\n- `Linux >= cc4e3835eff474aa274d6e1d18f69d9d296d3b76 < 9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7`\n- `Linux >= cc4e3835eff474aa274d6e1d18f69d9d296d3b76 < 54292b167466cdf42176b7b6f01da66c184deb12`\n- `Linux >= cc4e3835eff474aa274d6e1d18f69d9d296d3b76 < ecf69d4b43370c587e48d4d70289dbdb7e039d4d`\n- `Linux 5.9`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}