{"id":"CVE-2026-72405","state":"PUBLISHED","title":"net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync","description":"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() 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.","publishedAt":"2026-08-15T05:56:29.466Z","updatedAt":"2026-10-30T12:29:18.903Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cc4e3835eff474aa274d6e1d18f69d9d296d3b76","status":"affected","lessThan":"d59d3b19e1cd1a01a6db59705327387a30aed153","versionType":"git"},{"version":"cc4e3835eff474aa274d6e1d18f69d9d296d3b76","status":"affected","lessThan":"f49ed02fd8c98da823fdd7b00d64a8cc1d1883ac","versionType":"git"},{"version":"cc4e3835eff474aa274d6e1d18f69d9d296d3b76","status":"affected","lessThan":"cee6688e5731c0591643521716d1a1a5c1a98bf8","versionType":"git"},{"version":"cc4e3835eff474aa274d6e1d18f69d9d296d3b76","status":"affected","lessThan":"9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7","versionType":"git"},{"version":"cc4e3835eff474aa274d6e1d18f69d9d296d3b76","status":"affected","lessThan":"54292b167466cdf42176b7b6f01da66c184deb12","versionType":"git"},{"version":"cc4e3835eff474aa274d6e1d18f69d9d296d3b76","status":"affected","lessThan":"ecf69d4b43370c587e48d4d70289dbdb7e039d4d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/udp_tunnel_nic.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.9","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/udp_tunnel_nic.c"]}],"references":["https://git.kernel.org/stable/c/d59d3b19e1cd1a01a6db59705327387a30aed153","https://git.kernel.org/stable/c/f49ed02fd8c98da823fdd7b00d64a8cc1d1883ac","https://git.kernel.org/stable/c/cee6688e5731c0591643521716d1a1a5c1a98bf8","https://git.kernel.org/stable/c/9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7","https://git.kernel.org/stable/c/54292b167466cdf42176b7b6f01da66c184deb12","https://git.kernel.org/stable/c/ecf69d4b43370c587e48d4d70289dbdb7e039d4d"],"weaknesses":[],"ingestedAt":"2026-10-30T12:48:04.825Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/72xxx/CVE-2026-72405.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72405","state":"PUBLISHED","datePublished":"2026-08-15T05:56:29.466Z","dateUpdated":"2026-10-30T12:29:18.903Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-09T03:40:39.925Z"},"containers":{"cna":{"title":"net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync","descriptions":[{"lang":"en","value":"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() 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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cc4e3835eff474aa274d6e1d18f69d9d296d3b76","status":"affected","lessThan":"d59d3b19e1cd1a01a6db59705327387a30aed153","versionType":"git"},{"version":"cc4e3835eff474aa274d6e1d18f69d9d296d3b76","status":"affected","lessThan":"f49ed02fd8c98da823fdd7b00d64a8cc1d1883ac","versionType":"git"},{"version":"cc4e3835eff474aa274d6e1d18f69d9d296d3b76","status":"affected","lessThan":"cee6688e5731c0591643521716d1a1a5c1a98bf8","versionType":"git"},{"version":"cc4e3835eff474aa274d6e1d18f69d9d296d3b76","status":"affected","lessThan":"9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7","versionType":"git"},{"version":"cc4e3835eff474aa274d6e1d18f69d9d296d3b76","status":"affected","lessThan":"54292b167466cdf42176b7b6f01da66c184deb12","versionType":"git"},{"version":"cc4e3835eff474aa274d6e1d18f69d9d296d3b76","status":"affected","lessThan":"ecf69d4b43370c587e48d4d70289dbdb7e039d4d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/udp_tunnel_nic.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.9","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/udp_tunnel_nic.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/d59d3b19e1cd1a01a6db59705327387a30aed153"},{"url":"https://git.kernel.org/stable/c/f49ed02fd8c98da823fdd7b00d64a8cc1d1883ac"},{"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"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bug is reached only through local netlink/RTNL paths (VXLAN/Geneve tunnel socket create/delete, netdev feature updates, or netdev unregister) that queue udp_tunnel_nic_device_sync; remote UDP/VXLAN packets do not enter this offload management code.\nAC:L - An attacker can reliably win the race by running concurrent tunnel create/delete or netdev operations in multiple threads; both the double-queue and the premature free depend on attacker-controlled timing, not on uncontrollable system state.\nPR:L - Triggering udp_tunnel_notify_add/del_rx_port requires CAP_NET_ADMIN (e.g. ip link add/del vxlan/geneve), which unprivileged users can obtain in a user/network namespace via unshare; no remote or pre-auth network path exists.\nUI:N - Exploitation requires only programmatic tunnel or netdev manipulation via netlink; no victim user action such as opening a file or mounting a filesystem is needed.\nS:U - Impact is kernel heap corruption and potential privilege escalation within the same kernel/host security domain; it does not by itself cross a VM, container, or IOMMU boundary to another authority.\nC:H - The flaw is a use-after-free of struct udp_tunnel_nic; freed offload state can be reallocated and read through the still-queued work handler, enabling arbitrary kernel memory disclosure.\nI:H - UAF on the udp_tunnel_nic work item and its entries allows heap grooming and corrupting kernel objects/driver callbacks, supporting arbitrary write and potential kernel code execution.\nA:H - Use-after-free in a workqueue handler on a shared offload path can cause kernel oops/panic or wedged NIC offload during concurrent tunnel churn, producing total loss of availability."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:29:18.903Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.9","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.9","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.9","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.9","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.9","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.9","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-72405","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T18:49:07.638343Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T18:55:21.945Z"}}]}}}