{"cve":{"cve_id":"CVE-2026-46319","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":0.00125,"epss_percentile":0.02529,"epss_as_of":"2026-06-23","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_ct: Only release RCU read lock after ct_ft\n\nWhen looking up a flow table in act_ct in tcf_ct_flow_table_get(),\nrhashtable_lookup_fast() internally opens and closes an RCU read critical\nsection before returning ct_ft.\nThe tcf_ct_flow_table_cleanup_work() can complete before refcount_inc_not_zero()\nis invoked on the returned ct_ft resulting in a UAF on the already freed ct_ft\nobject. This vulnerability can lead to privilege escalation.\n\nAnalysis from zdi-disclosures@trendmicro.com:\nWhen initializing act_ct, tcf_ct_init() is called, which internally triggers\ntcf_ct_flow_table_get().\n\nstatic int tcf_ct_flow_table_get(struct net *net, struct tcf_ct_params *params)\n\n{\n                struct zones_ht_key key = { .net = net, .zone = params->zone };\n                struct tcf_ct_flow_table *ct_ft;\n                int err = -ENOMEM;\n\n                mutex_lock(&zones_mutex);\n                ct_ft = rhashtable_lookup_fast(&zones_ht, &key, zones_params); // [1]\n                if (ct_ft && refcount_inc_not_zero(&ct_ft->ref)) // [2]\n                                goto out_unlock;\n                ...\n}\n\nstatic __always_inline void *rhashtable_lookup_fast(\n                struct rhashtable *ht, const void *key,\n                const struct rhashtable_params params)\n{\n                void *obj;\n\n                rcu_read_lock();\n                obj = rhashtable_lookup(ht, key, params);\n                rcu_read_unlock();\n\n                return obj;\n}\n\nAt [1], rhashtable_lookup_fast() looks up and returns the corresponding ct_ft\nfrom zones_ht . The lookup is performed within an RCU read critical section\nthrough rcu_read_lock() / rcu_read_unlock(), which prevents the object from\nbeing freed. However, at the point of function return, rcu_read_unlock() has\nalready been called, and there is nothing preventing ct_ft from being freed\nbefore reaching refcount_inc_not_zero(&ct_ft->ref) at [2]. This interval becomes\nthe race window, during which ct_ft can be freed.\n\nFree Process:\n\ntcf_ct_flow_table_put() is executed through the path tcf_ct_cleanup() call_rcu()\ntcf_ct_params_free_rcu() tcf_ct_params_free() tcf_ct_flow_table_put().\n\nstatic void tcf_ct_flow_table_put(struct tcf_ct_flow_table *ct_ft)\n{\n                if (refcount_dec_and_test(&ct_ft->ref)) {\n                                rhashtable_remove_fast(&zones_ht, &ct_ft->node, zones_params);\n                                INIT_RCU_WORK(&ct_ft->rwork, tcf_ct_flow_table_cleanup_work); // [3]\n                                queue_rcu_work(act_ct_wq, &ct_ft->rwork);\n                }\n}\n\nAt [3], tcf_ct_flow_table_cleanup_work() is scheduled as RCU work\n\nstatic void tcf_ct_flow_table_cleanup_work(struct work_struct *work)\n\n{\n                struct tcf_ct_flow_table *ct_ft;\n                struct flow_block *block;\n\n                ct_ft = container_of(to_rcu_work(work), struct tcf_ct_flow_table,\n                                                                rwork);\n                nf_flow_table_free(&ct_ft->nf_ft);\n                block = &ct_ft->nf_ft.flow_block;\n                down_write(&ct_ft->nf_ft.flow_block_lock);\n                WARN_ON(!list_empty(&block->cb_list));\n                up_write(&ct_ft->nf_ft.flow_block_lock);\n                kfree(ct_ft); // [4]\n\n                module_put(THIS_MODULE);\n}\n\ntcf_ct_flow_table_cleanup_work() frees ct_ft at [4]. When this function executes\nbetween [1] and [2], UAF occurs.\n\nThis race condition has a very short race window, making it generally\ndifficult to trigger. Therefore, to trigger the vulnerability an msleep(100) was\ninserted after[1]","published_at":"2026-06-09T12:11:12.128000Z","last_modified_at":null,"cvss_v3_score":7.8,"cvss_v3_vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvss_v3_severity":"HIGH","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":null,"nvd_references":["https://git.kernel.org/stable/c/ece578ca61e572df96cfc80456357ebfae0b4b9e","https://git.kernel.org/stable/c/a2e0c045c87aa252eb61412e67dd91f2c2b19f81","https://git.kernel.org/stable/c/67c9ecc9f2575273ed1323e312881fc98ac83d6d","https://git.kernel.org/stable/c/f23424a0ddadb494d4bd57056a7ca703312d3a7b","https://git.kernel.org/stable/c/17dfb67cb399b660105d9a8c6100851c0d0cdc70","https://git.kernel.org/stable/c/4c727c6967a41b37efe0f26332ca9ec5b74785a3","https://git.kernel.org/stable/c/3e20e1b3058e0b94638e7b931c138e840e266724","https://git.kernel.org/stable/c/f462dca0c8415bf0058d0ffa476354c4476d0f09"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:39.878444Z","updated_at":"2026-06-28T23:30:37.146260Z"},"effective_severity":"HIGH","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"L","value_label":"Local"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"L","value_label":"Low"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"H","value_label":"High"},{"metric":"I","name":"Integrity","value":"H","value_label":"High"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"138470a9b2cc2e26e6018300394afc3858a54e6a","version_start_inclusive":true,"version_end":"ece578ca61e572df96cfc80456357ebfae0b4b9e","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:138470a9b2cc2e26e6018300394afc3858a54e6a:ece578ca61e572df96cfc80456357ebfae0b4b9e"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"138470a9b2cc2e26e6018300394afc3858a54e6a","version_start_inclusive":true,"version_end":"a2e0c045c87aa252eb61412e67dd91f2c2b19f81","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:138470a9b2cc2e26e6018300394afc3858a54e6a:a2e0c045c87aa252eb61412e67dd91f2c2b19f81"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"138470a9b2cc2e26e6018300394afc3858a54e6a","version_start_inclusive":true,"version_end":"67c9ecc9f2575273ed1323e312881fc98ac83d6d","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:138470a9b2cc2e26e6018300394afc3858a54e6a:67c9ecc9f2575273ed1323e312881fc98ac83d6d"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"138470a9b2cc2e26e6018300394afc3858a54e6a","version_start_inclusive":true,"version_end":"f23424a0ddadb494d4bd57056a7ca703312d3a7b","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:138470a9b2cc2e26e6018300394afc3858a54e6a:f23424a0ddadb494d4bd57056a7ca703312d3a7b"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"138470a9b2cc2e26e6018300394afc3858a54e6a","version_start_inclusive":true,"version_end":"17dfb67cb399b660105d9a8c6100851c0d0cdc70","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:138470a9b2cc2e26e6018300394afc3858a54e6a:17dfb67cb399b660105d9a8c6100851c0d0cdc70"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"138470a9b2cc2e26e6018300394afc3858a54e6a","version_start_inclusive":true,"version_end":"4c727c6967a41b37efe0f26332ca9ec5b74785a3","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:138470a9b2cc2e26e6018300394afc3858a54e6a:4c727c6967a41b37efe0f26332ca9ec5b74785a3"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"138470a9b2cc2e26e6018300394afc3858a54e6a","version_start_inclusive":true,"version_end":"3e20e1b3058e0b94638e7b931c138e840e266724","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:138470a9b2cc2e26e6018300394afc3858a54e6a:3e20e1b3058e0b94638e7b931c138e840e266724"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"138470a9b2cc2e26e6018300394afc3858a54e6a","version_start_inclusive":true,"version_end":"f462dca0c8415bf0058d0ffa476354c4476d0f09","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:138470a9b2cc2e26e6018300394afc3858a54e6a:f462dca0c8415bf0058d0ffa476354c4476d0f09"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"5.7","version_start_inclusive":true,"version_end":"5.7","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:5.7:5.7"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"0","version_start_inclusive":true,"version_end":"5.7","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:0:5.7"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"5.10.258","version_start_inclusive":true,"version_end":"5.10.*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:5.10.258:5.10.*"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"5.15.209","version_start_inclusive":true,"version_end":"5.15.*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:5.15.209:5.15.*"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"6.1.175","version_start_inclusive":true,"version_end":"6.1.*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:6.1.175:6.1.*"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"6.6.141","version_start_inclusive":true,"version_end":"6.6.*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:6.6.141:6.6.*"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"6.12.91","version_start_inclusive":true,"version_end":"6.12.*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:6.12.91:6.12.*"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"6.18.33","version_start_inclusive":true,"version_end":"6.18.*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:6.18.33:6.18.*"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"7.0.10","version_start_inclusive":true,"version_end":"7.0.*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:7.0.10:7.0.*"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"7.1","version_start_inclusive":true,"version_end":"*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:7.1:*"}],"exploit_refs":[],"news":[],"references":[{"url":"https://git.kernel.org/stable/c/ece578ca61e572df96cfc80456357ebfae0b4b9e","source_type":"MISC","tags":[]},{"url":"https://git.kernel.org/stable/c/a2e0c045c87aa252eb61412e67dd91f2c2b19f81","source_type":"MISC","tags":[]},{"url":"https://git.kernel.org/stable/c/67c9ecc9f2575273ed1323e312881fc98ac83d6d","source_type":"MISC","tags":[]},{"url":"https://git.kernel.org/stable/c/f23424a0ddadb494d4bd57056a7ca703312d3a7b","source_type":"MISC","tags":[]},{"url":"https://git.kernel.org/stable/c/17dfb67cb399b660105d9a8c6100851c0d0cdc70","source_type":"MISC","tags":[]},{"url":"https://git.kernel.org/stable/c/4c727c6967a41b37efe0f26332ca9ec5b74785a3","source_type":"MISC","tags":[]},{"url":"https://git.kernel.org/stable/c/3e20e1b3058e0b94638e7b931c138e840e266724","source_type":"MISC","tags":[]},{"url":"https://git.kernel.org/stable/c/f462dca0c8415bf0058d0ffa476354c4476d0f09","source_type":"MISC","tags":[]}],"timeline":[{"type":"published","at":"2026-06-09T12:11:12.128000Z","label":"CVE published","source":null},{"type":"cvss_changed","at":"2026-06-28T17:54:49.174395Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:54:49.174395Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:54:49.174395Z","label":"CVSS score revised","source":"cvelistv5"}]}