{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-46319", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-13T15:03:33.112Z", "datePublished": "2026-06-09T12:11:12.128Z", "dateUpdated": "2026-06-14T18:08:57.070Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-06-14T18:08:57.070Z"}, "descriptions": [{"lang": "en", "value": "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]"}], "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"}}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/sched/act_ct.c"], "versions": [{"version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "lessThan": "ece578ca61e572df96cfc80456357ebfae0b4b9e", "status": "affected", "versionType": "git"}, {"version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "lessThan": "a2e0c045c87aa252eb61412e67dd91f2c2b19f81", "status": "affected", "versionType": "git"}, {"version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "lessThan": "67c9ecc9f2575273ed1323e312881fc98ac83d6d", "status": "affected", "versionType": "git"}, {"version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "lessThan": "f23424a0ddadb494d4bd57056a7ca703312d3a7b", "status": "affected", "versionType": "git"}, {"version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "lessThan": "17dfb67cb399b660105d9a8c6100851c0d0cdc70", "status": "affected", "versionType": "git"}, {"version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "lessThan": "4c727c6967a41b37efe0f26332ca9ec5b74785a3", "status": "affected", "versionType": "git"}, {"version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "lessThan": "3e20e1b3058e0b94638e7b931c138e840e266724", "status": "affected", "versionType": "git"}, {"version": "138470a9b2cc2e26e6018300394afc3858a54e6a", "lessThan": "f462dca0c8415bf0058d0ffa476354c4476d0f09", "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/sched/act_ct.c"], "versions": [{"version": "5.7", "status": "affected"}, {"version": "0", "lessThan": "5.7", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.258", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.209", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.175", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.141", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.91", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.33", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.10", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1", "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": "5.7", "versionEndExcluding": "5.10.258"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "5.15.209"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.1.175"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.6.141"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.12.91"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.18.33"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.0.10"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/ece578ca61e572df96cfc80456357ebfae0b4b9e"}, {"url": "https://git.kernel.org/stable/c/a2e0c045c87aa252eb61412e67dd91f2c2b19f81"}, {"url": "https://git.kernel.org/stable/c/67c9ecc9f2575273ed1323e312881fc98ac83d6d"}, {"url": "https://git.kernel.org/stable/c/f23424a0ddadb494d4bd57056a7ca703312d3a7b"}, {"url": "https://git.kernel.org/stable/c/17dfb67cb399b660105d9a8c6100851c0d0cdc70"}, {"url": "https://git.kernel.org/stable/c/4c727c6967a41b37efe0f26332ca9ec5b74785a3"}, {"url": "https://git.kernel.org/stable/c/3e20e1b3058e0b94638e7b931c138e840e266724"}, {"url": "https://git.kernel.org/stable/c/f462dca0c8415bf0058d0ffa476354c4476d0f09"}], "title": "net/sched: act_ct: Only release RCU read lock after ct_ft", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "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]"}], "id": "CVE-2026-46319", "lastModified": "2026-06-14T06:16:24.420", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-06-09T13:16:37.210", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/17dfb67cb399b660105d9a8c6100851c0d0cdc70"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/3e20e1b3058e0b94638e7b931c138e840e266724"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4c727c6967a41b37efe0f26332ca9ec5b74785a3"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/67c9ecc9f2575273ed1323e312881fc98ac83d6d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a2e0c045c87aa252eb61412e67dd91f2c2b19f81"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ece578ca61e572df96cfc80456357ebfae0b4b9e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f23424a0ddadb494d4bd57056a7ca703312d3a7b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f462dca0c8415bf0058d0ffa476354c4476d0f09"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: net/sched: act_ct: Only release RCU read lock after ct_ft", "id": "2486979", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2486979"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-826", "details": ["A flaw was found in the Linux kernel. A race condition in the `act_ct` module, specifically during the flow table lookup, can lead to a Use-After-Free (UAF) vulnerability. This occurs because a critical lock is released prematurely, allowing a memory object to be freed while still in use. An attacker could potentially exploit this to achieve privilege escalation."], "name": "CVE-2026-46319", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-06-09T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-46319\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-46319\nhttps://lore.kernel.org/linux-cve-announce/2026060925-CVE-2026-46319-ab3d@gregkh/T"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[138470a9b2cc2e26e6018300394afc3858a54e6a,ece578ca61e572df96cfc80456357ebfae0b4b9e)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[138470a9b2cc2e26e6018300394afc3858a54e6a,a2e0c045c87aa252eb61412e67dd91f2c2b19f81)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[138470a9b2cc2e26e6018300394afc3858a54e6a,67c9ecc9f2575273ed1323e312881fc98ac83d6d)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[138470a9b2cc2e26e6018300394afc3858a54e6a,f23424a0ddadb494d4bd57056a7ca703312d3a7b)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[138470a9b2cc2e26e6018300394afc3858a54e6a,17dfb67cb399b660105d9a8c6100851c0d0cdc70)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[138470a9b2cc2e26e6018300394afc3858a54e6a,4c727c6967a41b37efe0f26332ca9ec5b74785a3)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[138470a9b2cc2e26e6018300394afc3858a54e6a,3e20e1b3058e0b94638e7b931c138e840e266724)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[138470a9b2cc2e26e6018300394afc3858a54e6a,f462dca0c8415bf0058d0ffa476354c4476d0f09)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "5.7"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,5.7)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.10.258,6.0.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.15.209,6.0.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.1.175,7.0.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.141,7.0.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.91,7.0.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.33,7.0.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.0.10,8.0.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.1-rc1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-06-09T13:30:04.959205+00:00", "updated": "2026-06-14T07:00:17.847008+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}