{"api_version":"1","generated_at":"2026-04-22T19:52:04+00:00","cve":"CVE-2026-23270","urls":{"html":"https://cve.report/CVE-2026-23270","api":"https://cve.report/api/cve/CVE-2026-23270.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-23270","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-23270"},"summary":{"title":"net/sched: Only allow act_ct to bind to clsact/ingress qdiscs and shared blocks","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: Only allow act_ct to bind to clsact/ingress qdiscs and shared blocks\n\nAs Paolo said earlier [1]:\n\n\"Since the blamed commit below, classify can return TC_ACT_CONSUMED while\nthe current skb being held by the defragmentation engine. As reported by\nGangMin Kim, if such packet is that may cause a UaF when the defrag engine\nlater on tries to tuch again such packet.\"\n\nact_ct was never meant to be used in the egress path, however some users\nare attaching it to egress today [2]. Attempting to reach a middle\nground, we noticed that, while most qdiscs are not handling\nTC_ACT_CONSUMED, clsact/ingress qdiscs are. With that in mind, we\naddress the issue by only allowing act_ct to bind to clsact/ingress\nqdiscs and shared blocks. That way it's still possible to attach act_ct to\negress (albeit only with clsact).\n\n[1] https://lore.kernel.org/netdev/674b8cbfc385c6f37fb29a1de08d8fe5c2b0fbee.1771321118.git.pabeni@redhat.com/\n[2] https://lore.kernel.org/netdev/cc6bfb4a-4a2b-42d8-b9ce-7ef6644fb22b@ovn.org/","state":"PUBLISHED","assigner":"Linux","published_at":"2026-03-18 18:16:26","updated_at":"2026-04-18 09:16:15"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"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","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/bc4e5bb529823a09f02dbe96169de679a9db26e0","name":"https://git.kernel.org/stable/c/bc4e5bb529823a09f02dbe96169de679a9db26e0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/11cb63b0d1a0685e0831ae3c77223e002ef18189","name":"https://git.kernel.org/stable/c/11cb63b0d1a0685e0831ae3c77223e002ef18189","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5a110ddcc99bda77a28598b3555fe009eaab3828","name":"https://git.kernel.org/stable/c/5a110ddcc99bda77a28598b3555fe009eaab3828","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/524ce8b4ea8f64900b6c52b6a28df74f6bc0801e","name":"https://git.kernel.org/stable/c/524ce8b4ea8f64900b6c52b6a28df74f6bc0801e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/380ad8b7c65ea7aa10ef2258297079ed5ac1f5b6","name":"https://git.kernel.org/stable/c/380ad8b7c65ea7aa10ef2258297079ed5ac1f5b6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9deda0fcda5c1f388c5e279541850b71a2ccfcf4","name":"https://git.kernel.org/stable/c/9deda0fcda5c1f388c5e279541850b71a2ccfcf4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/fb3c380a54e33d1fd272cc342faa906d787d7ef1","name":"https://git.kernel.org/stable/c/fb3c380a54e33d1fd272cc342faa906d787d7ef1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-23270","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23270","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 172ba7d46c202e679f3ccb10264c67416aaeb1c4 bc4e5bb529823a09f02dbe96169de679a9db26e0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0b5b831122fc3789fff75be433ba3e4dd7b779d4 fb3c380a54e33d1fd272cc342faa906d787d7ef1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 73f7da5fd124f2cda9161e2e46114915e6e82e97 5a110ddcc99bda77a28598b3555fe009eaab3828 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3f14b377d01d8357eba032b4cabc8c1149b458b6 524ce8b4ea8f64900b6c52b6a28df74f6bc0801e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: Only allow act_ct to bind to clsact/ingress qdiscs and shared blocks\n\nAs Paolo said earlier [1]:\n\n\"Since the blamed commit below, classify can return TC_ACT_CONSUMED while\nthe current skb being held by the defragmentation engine. As reported by\nGangMin Kim, if such packet is that may cause a UaF when the defrag engine\nlater on tries to tuch again such packet.\"\n\nact_ct was never meant to be used in the egress path, however some users\nare attaching it to egress today [2]. Attempting to reach a middle\nground, we noticed that, while most qdiscs are not handling\nTC_ACT_CONSUMED, clsact/ingress qdiscs are. With that in mind, we\naddress the issue by only allowing act_ct to bind to clsact/ingress\nqdiscs and shared blocks. That way it's still possible to attach act_ct to\negress (albeit only with clsact).\n\n[1] https://lore.kernel.org/netdev/674b8cbfc385c6f37fb29a1de08d8fe5c2b0fbee.1771321118.git.pabeni@redhat.com/\n[2] https://lore.kernel.org/netdev/cc6bfb4a-4a2b-42d8-b9ce-7ef6644fb22b@ovn.org/"}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-04-18T08:57:30.870Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/bc4e5bb529823a09f02dbe96169de679a9db26e0"},{"url":"https://git.kernel.org/stable/c/fb3c380a54e33d1fd272cc342faa906d787d7ef1"},{"url":"https://git.kernel.org/stable/c/5a110ddcc99bda77a28598b3555fe009eaab3828"},{"url":"https://git.kernel.org/stable/c/524ce8b4ea8f64900b6c52b6a28df74f6bc0801e"},{"url":"https://git.kernel.org/stable/c/380ad8b7c65ea7aa10ef2258297079ed5ac1f5b6"},{"url":"https://git.kernel.org/stable/c/9deda0fcda5c1f388c5e279541850b71a2ccfcf4"},{"url":"https://git.kernel.org/stable/c/11cb63b0d1a0685e0831ae3c77223e002ef18189"}],"title":"net/sched: Only allow act_ct to bind to clsact/ingress qdiscs and shared blocks","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-23270","datePublished":"2026-03-18T17:54:43.803Z","dateReserved":"2026-01-13T15:37:45.991Z","dateUpdated":"2026-04-18T08:57:30.870Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-03-18 18:16:26","lastModifiedDate":"2026-04-18 09:16:15","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"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","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"23270","Ordinal":"1","Title":"net/sched: Only allow act_ct to bind to clsact/ingress qdiscs an","CVE":"CVE-2026-23270","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"23270","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: Only allow act_ct to bind to clsact/ingress qdiscs and shared blocks\n\nAs Paolo said earlier [1]:\n\n\"Since the blamed commit below, classify can return TC_ACT_CONSUMED while\nthe current skb being held by the defragmentation engine. As reported by\nGangMin Kim, if such packet is that may cause a UaF when the defrag engine\nlater on tries to tuch again such packet.\"\n\nact_ct was never meant to be used in the egress path, however some users\nare attaching it to egress today [2]. Attempting to reach a middle\nground, we noticed that, while most qdiscs are not handling\nTC_ACT_CONSUMED, clsact/ingress qdiscs are. With that in mind, we\naddress the issue by only allowing act_ct to bind to clsact/ingress\nqdiscs and shared blocks. That way it's still possible to attach act_ct to\negress (albeit only with clsact).\n\n[1] https://lore.kernel.org/netdev/674b8cbfc385c6f37fb29a1de08d8fe5c2b0fbee.1771321118.git.pabeni@redhat.com/\n[2] https://lore.kernel.org/netdev/cc6bfb4a-4a2b-42d8-b9ce-7ef6644fb22b@ovn.org/","Type":"Description","Title":"net/sched: Only allow act_ct to bind to clsact/ingress qdiscs an"}]}}}