{"api_version":"1","generated_at":"2026-06-02T23:40:11+00:00","cve":"CVE-2026-45840","urls":{"html":"https://cve.report/CVE-2026-45840","api":"https://cve.report/api/cve/CVE-2026-45840.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-45840","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-45840"},"summary":{"title":"openvswitch: cap upcall PID array size and pre-size vport replies","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nopenvswitch: cap upcall PID array size and pre-size vport replies\n\nThe vport netlink reply helpers allocate a fixed-size skb with\nnlmsg_new(NLMSG_DEFAULT_SIZE, ...) but serialize the full upcall PID\narray via ovs_vport_get_upcall_portids().  Since\novs_vport_set_upcall_portids() accepts any non-zero multiple of\nsizeof(u32) with no upper bound, a CAP_NET_ADMIN user can install a PID\narray large enough to overflow the reply buffer, causing nla_put() to\nfail with -EMSGSIZE and hitting BUG_ON(err < 0).  On systems with\nunprivileged user namespaces enabled (e.g., Ubuntu default), this is\nreachable via unshare -Urn since OVS vport mutation operations use\nGENL_UNS_ADMIN_PERM.\n\n kernel BUG at net/openvswitch/datapath.c:2414!\n Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI\n CPU: 1 UID: 0 PID: 65 Comm: poc Not tainted 7.0.0-rc7-00195-geb216e422044 #1\n RIP: 0010:ovs_vport_cmd_set+0x34c/0x400\n Call Trace:\n  <TASK>\n  genl_family_rcv_msg_doit (net/netlink/genetlink.c:1116)\n  genl_rcv_msg (net/netlink/genetlink.c:1194)\n  netlink_rcv_skb (net/netlink/af_netlink.c:2550)\n  genl_rcv (net/netlink/genetlink.c:1219)\n  netlink_unicast (net/netlink/af_netlink.c:1344)\n  netlink_sendmsg (net/netlink/af_netlink.c:1894)\n  __sys_sendto (net/socket.c:2206)\n  __x64_sys_sendto (net/socket.c:2209)\n  do_syscall_64 (arch/x86/entry/syscall_64.c:63)\n  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n  </TASK>\n Kernel panic - not syncing: Fatal exception\n\nReject attempts to set more PIDs than nr_cpu_ids in\novs_vport_set_upcall_portids(), and pre-compute the worst-case reply\nsize in ovs_vport_cmd_msg_size() based on that bound, similar to the\nexisting ovs_dp_cmd_msg_size().  nr_cpu_ids matches the cap already\nused by the per-CPU dispatch configuration on the datapath side\n(ovs_dp_cmd_fill_info() serialises at most nr_cpu_ids PIDs), so the\ntwo sides stay consistent.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-27 11:16:23","updated_at":"2026-06-01 17:17:12"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/b39f763d720d623218bc1d95ace6855d7b474e81","name":"https://git.kernel.org/stable/c/b39f763d720d623218bc1d95ace6855d7b474e81","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1d6c02b86329883aa467a3a61f8d34369db73a2f","name":"https://git.kernel.org/stable/c/1d6c02b86329883aa467a3a61f8d34369db73a2f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/fa6e90bc443bed8dc0d55bc5ea5b27ffdfe37704","name":"https://git.kernel.org/stable/c/fa6e90bc443bed8dc0d55bc5ea5b27ffdfe37704","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2091c6aa0df6aba47deb5c8ab232b1cb60af3519","name":"https://git.kernel.org/stable/c/2091c6aa0df6aba47deb5c8ab232b1cb60af3519","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d9e47e29aacb9f8a9d59feb6ab5b128a9bbb40b0","name":"https://git.kernel.org/stable/c/d9e47e29aacb9f8a9d59feb6ab5b128a9bbb40b0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f99ac36b5d7c719d08a69fcdecce40f78a874e15","name":"https://git.kernel.org/stable/c/f99ac36b5d7c719d08a69fcdecce40f78a874e15","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f9ef3db77a383d66847fd082c2b437d8ae4d9c63","name":"https://git.kernel.org/stable/c/f9ef3db77a383d66847fd082c2b437d8ae4d9c63","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/8d59b80e69dddb665eb2de36e62859ab2073470e","name":"https://git.kernel.org/stable/c/8d59b80e69dddb665eb2de36e62859ab2073470e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-45840","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45840","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5cd667b0a4567048bb555927d6ee564f4e5620a9 8d59b80e69dddb665eb2de36e62859ab2073470e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5cd667b0a4567048bb555927d6ee564f4e5620a9 d9e47e29aacb9f8a9d59feb6ab5b128a9bbb40b0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5cd667b0a4567048bb555927d6ee564f4e5620a9 b39f763d720d623218bc1d95ace6855d7b474e81 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5cd667b0a4567048bb555927d6ee564f4e5620a9 f9ef3db77a383d66847fd082c2b437d8ae4d9c63 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5cd667b0a4567048bb555927d6ee564f4e5620a9 f99ac36b5d7c719d08a69fcdecce40f78a874e15 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5cd667b0a4567048bb555927d6ee564f4e5620a9 fa6e90bc443bed8dc0d55bc5ea5b27ffdfe37704 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5cd667b0a4567048bb555927d6ee564f4e5620a9 1d6c02b86329883aa467a3a61f8d34369db73a2f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5cd667b0a4567048bb555927d6ee564f4e5620a9 2091c6aa0df6aba47deb5c8ab232b1cb60af3519 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3.17","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 3.17 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.258 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.209 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.175 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.141 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.91 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.33 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.10 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"45840","cve":"CVE-2026-45840","epss":"0.000180000","percentile":"0.050770000","score_date":"2026-06-01","updated_at":"2026-06-02 00:05:19"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/openvswitch/datapath.c","net/openvswitch/vport.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"8d59b80e69dddb665eb2de36e62859ab2073470e","status":"affected","version":"5cd667b0a4567048bb555927d6ee564f4e5620a9","versionType":"git"},{"lessThan":"d9e47e29aacb9f8a9d59feb6ab5b128a9bbb40b0","status":"affected","version":"5cd667b0a4567048bb555927d6ee564f4e5620a9","versionType":"git"},{"lessThan":"b39f763d720d623218bc1d95ace6855d7b474e81","status":"affected","version":"5cd667b0a4567048bb555927d6ee564f4e5620a9","versionType":"git"},{"lessThan":"f9ef3db77a383d66847fd082c2b437d8ae4d9c63","status":"affected","version":"5cd667b0a4567048bb555927d6ee564f4e5620a9","versionType":"git"},{"lessThan":"f99ac36b5d7c719d08a69fcdecce40f78a874e15","status":"affected","version":"5cd667b0a4567048bb555927d6ee564f4e5620a9","versionType":"git"},{"lessThan":"fa6e90bc443bed8dc0d55bc5ea5b27ffdfe37704","status":"affected","version":"5cd667b0a4567048bb555927d6ee564f4e5620a9","versionType":"git"},{"lessThan":"1d6c02b86329883aa467a3a61f8d34369db73a2f","status":"affected","version":"5cd667b0a4567048bb555927d6ee564f4e5620a9","versionType":"git"},{"lessThan":"2091c6aa0df6aba47deb5c8ab232b1cb60af3519","status":"affected","version":"5cd667b0a4567048bb555927d6ee564f4e5620a9","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/openvswitch/datapath.c","net/openvswitch/vport.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"3.17"},{"lessThan":"3.17","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.258","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.209","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.175","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.141","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.91","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.33","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.10","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.258","versionStartIncluding":"3.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.209","versionStartIncluding":"3.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.175","versionStartIncluding":"3.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.141","versionStartIncluding":"3.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.91","versionStartIncluding":"3.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.33","versionStartIncluding":"3.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.10","versionStartIncluding":"3.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1-rc1","versionStartIncluding":"3.17","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nopenvswitch: cap upcall PID array size and pre-size vport replies\n\nThe vport netlink reply helpers allocate a fixed-size skb with\nnlmsg_new(NLMSG_DEFAULT_SIZE, ...) but serialize the full upcall PID\narray via ovs_vport_get_upcall_portids().  Since\novs_vport_set_upcall_portids() accepts any non-zero multiple of\nsizeof(u32) with no upper bound, a CAP_NET_ADMIN user can install a PID\narray large enough to overflow the reply buffer, causing nla_put() to\nfail with -EMSGSIZE and hitting BUG_ON(err < 0).  On systems with\nunprivileged user namespaces enabled (e.g., Ubuntu default), this is\nreachable via unshare -Urn since OVS vport mutation operations use\nGENL_UNS_ADMIN_PERM.\n\n kernel BUG at net/openvswitch/datapath.c:2414!\n Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI\n CPU: 1 UID: 0 PID: 65 Comm: poc Not tainted 7.0.0-rc7-00195-geb216e422044 #1\n RIP: 0010:ovs_vport_cmd_set+0x34c/0x400\n Call Trace:\n  <TASK>\n  genl_family_rcv_msg_doit (net/netlink/genetlink.c:1116)\n  genl_rcv_msg (net/netlink/genetlink.c:1194)\n  netlink_rcv_skb (net/netlink/af_netlink.c:2550)\n  genl_rcv (net/netlink/genetlink.c:1219)\n  netlink_unicast (net/netlink/af_netlink.c:1344)\n  netlink_sendmsg (net/netlink/af_netlink.c:1894)\n  __sys_sendto (net/socket.c:2206)\n  __x64_sys_sendto (net/socket.c:2209)\n  do_syscall_64 (arch/x86/entry/syscall_64.c:63)\n  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n  </TASK>\n Kernel panic - not syncing: Fatal exception\n\nReject attempts to set more PIDs than nr_cpu_ids in\novs_vport_set_upcall_portids(), and pre-compute the worst-case reply\nsize in ovs_vport_cmd_msg_size() based on that bound, similar to the\nexisting ovs_dp_cmd_msg_size().  nr_cpu_ids matches the cap already\nused by the per-CPU dispatch configuration on the datapath side\n(ovs_dp_cmd_fill_info() serialises at most nr_cpu_ids PIDs), so the\ntwo sides stay consistent."}],"providerMetadata":{"dateUpdated":"2026-06-01T16:16:26.160Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/8d59b80e69dddb665eb2de36e62859ab2073470e"},{"url":"https://git.kernel.org/stable/c/d9e47e29aacb9f8a9d59feb6ab5b128a9bbb40b0"},{"url":"https://git.kernel.org/stable/c/b39f763d720d623218bc1d95ace6855d7b474e81"},{"url":"https://git.kernel.org/stable/c/f9ef3db77a383d66847fd082c2b437d8ae4d9c63"},{"url":"https://git.kernel.org/stable/c/f99ac36b5d7c719d08a69fcdecce40f78a874e15"},{"url":"https://git.kernel.org/stable/c/fa6e90bc443bed8dc0d55bc5ea5b27ffdfe37704"},{"url":"https://git.kernel.org/stable/c/1d6c02b86329883aa467a3a61f8d34369db73a2f"},{"url":"https://git.kernel.org/stable/c/2091c6aa0df6aba47deb5c8ab232b1cb60af3519"}],"title":"openvswitch: cap upcall PID array size and pre-size vport replies","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-45840","datePublished":"2026-05-27T09:24:39.478Z","dateReserved":"2026-05-13T15:03:33.077Z","dateUpdated":"2026-06-01T16:16:26.160Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-27 11:16:23","lastModifiedDate":"2026-06-01 17:17:12","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"45840","Ordinal":"1","Title":"openvswitch: cap upcall PID array size and pre-size vport replie","CVE":"CVE-2026-45840","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"45840","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nopenvswitch: cap upcall PID array size and pre-size vport replies\n\nThe vport netlink reply helpers allocate a fixed-size skb with\nnlmsg_new(NLMSG_DEFAULT_SIZE, ...) but serialize the full upcall PID\narray via ovs_vport_get_upcall_portids().  Since\novs_vport_set_upcall_portids() accepts any non-zero multiple of\nsizeof(u32) with no upper bound, a CAP_NET_ADMIN user can install a PID\narray large enough to overflow the reply buffer, causing nla_put() to\nfail with -EMSGSIZE and hitting BUG_ON(err < 0).  On systems with\nunprivileged user namespaces enabled (e.g., Ubuntu default), this is\nreachable via unshare -Urn since OVS vport mutation operations use\nGENL_UNS_ADMIN_PERM.\n\n kernel BUG at net/openvswitch/datapath.c:2414!\n Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI\n CPU: 1 UID: 0 PID: 65 Comm: poc Not tainted 7.0.0-rc7-00195-geb216e422044 #1\n RIP: 0010:ovs_vport_cmd_set+0x34c/0x400\n Call Trace:\n  <TASK>\n  genl_family_rcv_msg_doit (net/netlink/genetlink.c:1116)\n  genl_rcv_msg (net/netlink/genetlink.c:1194)\n  netlink_rcv_skb (net/netlink/af_netlink.c:2550)\n  genl_rcv (net/netlink/genetlink.c:1219)\n  netlink_unicast (net/netlink/af_netlink.c:1344)\n  netlink_sendmsg (net/netlink/af_netlink.c:1894)\n  __sys_sendto (net/socket.c:2206)\n  __x64_sys_sendto (net/socket.c:2209)\n  do_syscall_64 (arch/x86/entry/syscall_64.c:63)\n  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n  </TASK>\n Kernel panic - not syncing: Fatal exception\n\nReject attempts to set more PIDs than nr_cpu_ids in\novs_vport_set_upcall_portids(), and pre-compute the worst-case reply\nsize in ovs_vport_cmd_msg_size() based on that bound, similar to the\nexisting ovs_dp_cmd_msg_size().  nr_cpu_ids matches the cap already\nused by the per-CPU dispatch configuration on the datapath side\n(ovs_dp_cmd_fill_info() serialises at most nr_cpu_ids PIDs), so the\ntwo sides stay consistent.","Type":"Description","Title":"openvswitch: cap upcall PID array size and pre-size vport replie"}]}}}