{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-72405", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.925Z", "datePublished": "2026-08-15T05:56:29.466Z", "dateUpdated": "2026-08-17T05:43:45.202Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:43:45.202Z" }, "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." } ], "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/udp_tunnel_nic.c" ], "versions": [ { "version": "cc4e3835eff474aa274d6e1d18f69d9d296d3b76", "lessThan": "cee6688e5731c0591643521716d1a1a5c1a98bf8", "status": "affected", "versionType": "git" }, { "version": "cc4e3835eff474aa274d6e1d18f69d9d296d3b76", "lessThan": "9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7", "status": "affected", "versionType": "git" }, { "version": "cc4e3835eff474aa274d6e1d18f69d9d296d3b76", "lessThan": "54292b167466cdf42176b7b6f01da66c184deb12", "status": "affected", "versionType": "git" }, { "version": "cc4e3835eff474aa274d6e1d18f69d9d296d3b76", "lessThan": "ecf69d4b43370c587e48d4d70289dbdb7e039d4d", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/udp_tunnel_nic.c" ], "versions": [ { "version": "5.9", "status": "affected" }, { "version": "0", "lessThan": "5.9", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "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" } ] } ] } ], "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" } ], "title": "net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync", "x_generator": { "engine": "bippy-1.2.0" } } } }