{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-46319", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-46319", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-06-09T12:11:12.128Z", "updatedAt": "2026-10-19T19:36:58.008Z", "importedAt": "2026-10-24T01:58:14.884Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "net/sched: act_ct: Only release RCU read lock after ct_ft", "summary": "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]", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "status": "affected", "versionType": "git", "lessThan": "ece578ca61e572df96cfc80456357ebfae0b4b9e" }, { "version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "status": "affected", "versionType": "git", "lessThan": "a2e0c045c87aa252eb61412e67dd91f2c2b19f81" }, { "version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "status": "affected", "versionType": "git", "lessThan": "67c9ecc9f2575273ed1323e312881fc98ac83d6d" }, { "version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "status": "affected", "versionType": "git", "lessThan": "f23424a0ddadb494d4bd57056a7ca703312d3a7b" }, { "version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "status": "affected", "versionType": "git", "lessThan": "17dfb67cb399b660105d9a8c6100851c0d0cdc70" }, { "version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "status": "affected", "versionType": "git", "lessThan": "4c727c6967a41b37efe0f26332ca9ec5b74785a3" }, { "version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "status": "affected", "versionType": "git", "lessThan": "3e20e1b3058e0b94638e7b931c138e840e266724" }, { "version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "status": "affected", "versionType": "git", "lessThan": "f462dca0c8415bf0058d0ffa476354c4476d0f09" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "5.7", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "5.7" }, { "version": "5.10.258", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.209", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.175", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.141", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.91", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.33", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.0.10", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.0.*" }, { "version": "7.1", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }