{"id":"CVE-2026-31678","state":"PUBLISHED","title":"openvswitch: defer tunnel netdev_put to RCU release","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nopenvswitch: defer tunnel netdev_put to RCU release\n\novs_netdev_tunnel_destroy() may run after NETDEV_UNREGISTER already\ndetached the device. Dropping the netdev reference in destroy can race\nwith concurrent readers that still observe vport->dev.\n\nDo not release vport->dev in ovs_netdev_tunnel_destroy(). Instead, let\nvport_netdev_free() drop the reference from the RCU callback, matching\nthe non-tunnel destroy path and avoiding additional synchronization\nunder RTNL.","publishedAt":"2026-04-25T08:46:54.476Z","updatedAt":"2026-10-30T12:24:33.112Z","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":"a9020fde67a6eb77f8130feff633189f99264db1","status":"affected","lessThan":"f0ec49d3a39c1f5a4f3270ea27ca0854fad2a2a2","versionType":"git"},{"version":"a9020fde67a6eb77f8130feff633189f99264db1","status":"affected","lessThan":"9d56aced21fb9c104e8a3f3be9b21fbafe448ffc","versionType":"git"},{"version":"a9020fde67a6eb77f8130feff633189f99264db1","status":"affected","lessThan":"42f0d3d81209654c08ffdde5a34b9b92d2645896","versionType":"git"},{"version":"a9020fde67a6eb77f8130feff633189f99264db1","status":"affected","lessThan":"bbe7bd722bfaea36aab3da6cc60fb4a05c644643","versionType":"git"},{"version":"a9020fde67a6eb77f8130feff633189f99264db1","status":"affected","lessThan":"98b726ab5e2a4811e27c28e4d041f75bba147eab","versionType":"git"},{"version":"a9020fde67a6eb77f8130feff633189f99264db1","status":"affected","lessThan":"b8c56a3fc5d879c0928f207a756b0f067f06c6a8","versionType":"git"},{"version":"a9020fde67a6eb77f8130feff633189f99264db1","status":"affected","lessThan":"6931d21f87bc6d657f145798fad0bf077b82486c","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/openvswitch/vport-netdev.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.3","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.168","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.131","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.80","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.21","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.11","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/openvswitch/vport-netdev.c"]}],"references":["https://git.kernel.org/stable/c/f0ec49d3a39c1f5a4f3270ea27ca0854fad2a2a2","https://git.kernel.org/stable/c/9d56aced21fb9c104e8a3f3be9b21fbafe448ffc","https://git.kernel.org/stable/c/42f0d3d81209654c08ffdde5a34b9b92d2645896","https://git.kernel.org/stable/c/bbe7bd722bfaea36aab3da6cc60fb4a05c644643","https://git.kernel.org/stable/c/98b726ab5e2a4811e27c28e4d041f75bba147eab","https://git.kernel.org/stable/c/b8c56a3fc5d879c0928f207a756b0f067f06c6a8","https://git.kernel.org/stable/c/6931d21f87bc6d657f145798fad0bf077b82486c"],"weaknesses":["CWE-362"],"ingestedAt":"2026-10-30T12:42:04.495Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31678.json","commit":"db8103c5921aac81d5d90efcf3745980dafabf49","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31678","state":"PUBLISHED","datePublished":"2026-04-25T08:46:54.476Z","dateUpdated":"2026-10-30T12:24:33.112Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.130Z"},"containers":{"cna":{"title":"openvswitch: defer tunnel netdev_put to RCU release","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nopenvswitch: defer tunnel netdev_put to RCU release\n\novs_netdev_tunnel_destroy() may run after NETDEV_UNREGISTER already\ndetached the device. Dropping the netdev reference in destroy can race\nwith concurrent readers that still observe vport->dev.\n\nDo not release vport->dev in ovs_netdev_tunnel_destroy(). Instead, let\nvport_netdev_free() drop the reference from the RCU callback, matching\nthe non-tunnel destroy path and avoiding additional synchronization\nunder RTNL."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a9020fde67a6eb77f8130feff633189f99264db1","status":"affected","lessThan":"f0ec49d3a39c1f5a4f3270ea27ca0854fad2a2a2","versionType":"git"},{"version":"a9020fde67a6eb77f8130feff633189f99264db1","status":"affected","lessThan":"9d56aced21fb9c104e8a3f3be9b21fbafe448ffc","versionType":"git"},{"version":"a9020fde67a6eb77f8130feff633189f99264db1","status":"affected","lessThan":"42f0d3d81209654c08ffdde5a34b9b92d2645896","versionType":"git"},{"version":"a9020fde67a6eb77f8130feff633189f99264db1","status":"affected","lessThan":"bbe7bd722bfaea36aab3da6cc60fb4a05c644643","versionType":"git"},{"version":"a9020fde67a6eb77f8130feff633189f99264db1","status":"affected","lessThan":"98b726ab5e2a4811e27c28e4d041f75bba147eab","versionType":"git"},{"version":"a9020fde67a6eb77f8130feff633189f99264db1","status":"affected","lessThan":"b8c56a3fc5d879c0928f207a756b0f067f06c6a8","versionType":"git"},{"version":"a9020fde67a6eb77f8130feff633189f99264db1","status":"affected","lessThan":"6931d21f87bc6d657f145798fad0bf077b82486c","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/openvswitch/vport-netdev.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.3","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.168","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.131","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.80","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.21","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.11","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/openvswitch/vport-netdev.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/f0ec49d3a39c1f5a4f3270ea27ca0854fad2a2a2"},{"url":"https://git.kernel.org/stable/c/9d56aced21fb9c104e8a3f3be9b21fbafe448ffc"},{"url":"https://git.kernel.org/stable/c/42f0d3d81209654c08ffdde5a34b9b92d2645896"},{"url":"https://git.kernel.org/stable/c/bbe7bd722bfaea36aab3da6cc60fb4a05c644643"},{"url":"https://git.kernel.org/stable/c/98b726ab5e2a4811e27c28e4d041f75bba147eab"},{"url":"https://git.kernel.org/stable/c/b8c56a3fc5d879c0928f207a756b0f067f06c6a8"},{"url":"https://git.kernel.org/stable/c/6931d21f87bc6d657f145798fad0bf077b82486c"}],"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 vulnerable destroy path is reached through local Generic Netlink/rtnetlink control operations that create or delete Open vSwitch tunnel vports. Remote tunnel packets alone do not invoke `ovs_netdev_tunnel_destroy()`.\nAC:L - This is a race/lifetime bug, but the attacker can control both sides by repeatedly deleting tunnel vports while concurrently driving RCU readers such as vport get/dump, packet execute, or datapath traffic. No rare external condition is required.\nPR:L - Creating and deleting OVS datapaths/vports requires `CAP_NET_ADMIN`, but the OVS Generic Netlink families are netns-aware and use `GENL_UNS_ADMIN_PERM`, making this reachable with CAP_NET_ADMIN in an unprivileged user namespace. This is Low privileges rather than High.\nUI:N - No victim user action is needed once the local attacker can issue the relevant netlink operations. The attacker can trigger creation, deletion, and racing reader activity directly.\nS:U - The vulnerability is a kernel memory lifetime error within the same host kernel security authority. It is a standard local kernel privilege-escalation/DoS class issue, not a VM or hardware boundary escape.\nC:H - The early `netdev_put()` can free the `net_device` while RCU readers still dereference `vport->dev`, creating a use-after-free. Per kernel CVSS guidance, UAFs are scored as High confidentiality impact because they can be developed into kernel memory disclosure primitives.\nI:H - The stale `net_device` pointer can be reused after free by kernel readers/writers and may reach function-pointer-bearing netdev paths. Per guidance, a use-after-free is scored as High integrity impact because heap reuse can enable arbitrary write or code execution.\nA:H - The bug can at minimum crash or oops the kernel through NULL/stale `vport->dev` dereferences and has related observed OVS netdev lifetime splats. A kernel UAF also warrants High availability impact."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:24:33.112Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"5.15.224"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"6.1.168"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"6.6.131"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"6.12.80"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"6.18.21"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"6.19.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-31678","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:12:17.787623Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-362","lang":"en","type":"CWE","description":"CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T18:56:04.200Z"}}]}}}