{"id":"CVE-2026-97611","summary":"net: openvswitch: fix use-after-free of the flow table mask array","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: fix use-after-free of the flow table mask array\n\ntbl_mask_array_realloc() retires the old mask_array before it stops being\nreachable:\n\n\told = ovsl_dereference(tbl-\u003emask_array);\n\tif (old) {\n\t\t...\n\t\tcall_rcu(&old-\u003ercu, mask_array_rcu_cb);\n\t}\n\n\trcu_assign_pointer(tbl-\u003emask_array, new);\n\ncall_rcu() only waits for read-side critical sections already in flight.\ntbl-\u003emask_array still points at old between the call_rcu() and the\nrcu_assign_pointer(), so a reader entering ovs_flow_tbl_lookup_stats() in\nthat window picks up old in a fresh critical section that the pending\ngrace period does not cover.\n\ntbl_mask_array_realloc() runs in process context under ovs_mutex, so the\nwindow is preemptible and can outlast the grace period. Then\nmask_array_rcu_cb() frees old before the swap runs:\n\n  BUG: KASAN: slab-use-after-free in flow_lookup.constprop.0+0x2bf/0x2f0\n  Read of size 8 at addr ffff888020b3e018 by task poc/741\n   flow_lookup.constprop.0+0x2bf/0x2f0\n   ovs_flow_tbl_lookup_stats+0x4a3/0x5c0\n   ovs_dp_process_packet+0x19c/0x710\n   ovs_vport_receive+0x243/0x390\n   internal_dev_xmit+0x81/0x170\n  Freed by task 728:\n   kfree+0x16a/0x4e0\n   rcu_core+0x853/0x1030\n\nPublish the new array before retiring the old one. The kfree_rcu() that\ncall_rcu() replaced ran after the swap.","modified":"2026-09-26T03:48:30.675944303Z","published":"2026-09-25T10:22:20.827Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97611.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/035e9c3722067648a99010711d0ce81f42572ef4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a0d18d21d48a551f82ee344e50efb8a682161489"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ba4ba11ed6eb8972c69070417fc27b48deb002e8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cd982e11684def5d4a9fcfd5354de09032828414"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97611.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97611"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"eac87c413bf9794c14d488998a5265ea5b32f04e"},{"fixed":"cd982e11684def5d4a9fcfd5354de09032828414"},{"fixed":"a0d18d21d48a551f82ee344e50efb8a682161489"},{"fixed":"035e9c3722067648a99010711d0ce81f42572ef4"},{"fixed":"ba4ba11ed6eb8972c69070417fc27b48deb002e8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97611.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.9.0"},{"fixed":"6.12.111"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.53"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97611.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}