{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-97611", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-24T16:01:01.158Z", "datePublished": "2026-09-25T10:22:20.827Z", "dateUpdated": "2026-10-19T09:10:15.022Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:10:15.022Z" }, "descriptions": [ { "lang": "en", "value": "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->mask_array);\n\tif (old) {\n\t\t...\n\t\tcall_rcu(&old->rcu, mask_array_rcu_cb);\n\t}\n\n\trcu_assign_pointer(tbl->mask_array, new);\n\ncall_rcu() only waits for read-side critical sections already in flight.\ntbl->mask_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." } ], "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 - Both sides of the race are driven locally: tbl_mask_array_realloc() runs from OVS_FLOW_CMD_NEW/DEL generic-netlink requests (flow insert/remove growing or shrinking the mask array), and the reader is ovs_flow_tbl_lookup_stats() fed by the attacker's own packets via internal_dev_xmit. No remote protocol carries data that causes the bug.\nAC:L - The attacker controls both sides, looping flow add/delete to trigger reallocs while transmitting on the datapath's internal port so lookups run. Failed attempts are harmless, the preemptible window can outlast a grace period, and the reporter's KASAN trace shows a PoC hit it.\nPR:L - The OVS datapath, vport and flow genl ops are GENL_UNS_ADMIN_PERM with netnsok=true, so CAP_NET_ADMIN in a user namespace (unshare -Urn) is enough to create a datapath, add flows and send packets through it.\nUI:N - No victim action is needed; the attacker creates the datapath, drives mask-array reallocation and generates the lookup traffic entirely by themselves.\nS:U - The impact stays within the kernel's own security authority, as ordinary kernel memory corruption leading to local privilege escalation; no VM or hardware boundary is crossed.\nC:H - flow_lookup() reads the freed struct mask_array (max, masks[] pointers) and dereferences masks[i] as sw_flow_mask. If the slab is reclaimed with attacker data, that gives controlled-pointer reads of kernel memory.\nI:H - On a flow hit, flow_lookup() does stats->usage_cntrs[index]++ through ma->masks_usage_stats taken from the freed mask_array, so a reclaimed object yields an attacker-steered kernel memory increment (write primitive).\nA:H - The slab use-after-free in flow_lookup() during ovs_dp_process_packet crashes the kernel (KASAN-reported); with a reclaimed object, wild pointer dereferences cause an oops or panic." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/openvswitch/flow_table.c" ], "versions": [ { "version": "eac87c413bf9794c14d488998a5265ea5b32f04e", "lessThan": "4c98b492e9ed63f9ca3e23566d9a6a4f235944f4", "status": "affected", "versionType": "git" }, { "version": "eac87c413bf9794c14d488998a5265ea5b32f04e", "lessThan": "4016ead17acd75312c066ecd47c4b7f0a81ceaa2", "status": "affected", "versionType": "git" }, { "version": "eac87c413bf9794c14d488998a5265ea5b32f04e", "lessThan": "017dbbf0d6c319a487f68e22f56d91fc787d5525", "status": "affected", "versionType": "git" }, { "version": "eac87c413bf9794c14d488998a5265ea5b32f04e", "lessThan": "76678217cdabc41e3c74c23b45b62086ffb8fe7a", "status": "affected", "versionType": "git" }, { "version": "eac87c413bf9794c14d488998a5265ea5b32f04e", "lessThan": "cd982e11684def5d4a9fcfd5354de09032828414", "status": "affected", "versionType": "git" }, { "version": "eac87c413bf9794c14d488998a5265ea5b32f04e", "lessThan": "a0d18d21d48a551f82ee344e50efb8a682161489", "status": "affected", "versionType": "git" }, { "version": "eac87c413bf9794c14d488998a5265ea5b32f04e", "lessThan": "035e9c3722067648a99010711d0ce81f42572ef4", "status": "affected", "versionType": "git" }, { "version": "eac87c413bf9794c14d488998a5265ea5b32f04e", "lessThan": "ba4ba11ed6eb8972c69070417fc27b48deb002e8", "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/openvswitch/flow_table.c" ], "versions": [ { "version": "5.9", "status": "affected" }, { "version": "0", "lessThan": "5.9", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.271", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.222", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.189", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.158", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.111", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.53", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.7", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "5.10.271" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9", "versionEndExcluding": "5.15.222" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9", "versionEndExcluding": "6.1.189" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9", "versionEndExcluding": "6.6.158" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9", "versionEndExcluding": "6.12.111" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9", "versionEndExcluding": "6.18.53" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9", "versionEndExcluding": "7.2.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/4c98b492e9ed63f9ca3e23566d9a6a4f235944f4" }, { "url": "https://git.kernel.org/stable/c/4016ead17acd75312c066ecd47c4b7f0a81ceaa2" }, { "url": "https://git.kernel.org/stable/c/017dbbf0d6c319a487f68e22f56d91fc787d5525" }, { "url": "https://git.kernel.org/stable/c/76678217cdabc41e3c74c23b45b62086ffb8fe7a" }, { "url": "https://git.kernel.org/stable/c/cd982e11684def5d4a9fcfd5354de09032828414" }, { "url": "https://git.kernel.org/stable/c/a0d18d21d48a551f82ee344e50efb8a682161489" }, { "url": "https://git.kernel.org/stable/c/035e9c3722067648a99010711d0ce81f42572ef4" }, { "url": "https://git.kernel.org/stable/c/ba4ba11ed6eb8972c69070417fc27b48deb002e8" } ], "title": "net: openvswitch: fix use-after-free of the flow table mask array", "x_generator": { "engine": "bippy-1.2.0" } } } }