{"id":"CVE-2026-64530","state":"PUBLISHED","title":"net/sched: cls_api: Handle TC_ACT_CONSUMED in tcf_qevent_handle","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_api: Handle TC_ACT_CONSUMED in tcf_qevent_handle\n\ntcf_classify() can return TC_ACT_CONSUMED while the skb is held by the\ndefragmentation engine (e.g. act_ct on out-of-order fragments). When\nthat happens the skb is no longer owned by the caller and must not be\ntouched again.\n\ntcf_qevent_handle() did not handle TC_ACT_CONSUMED: it fell through the\nswitch and returned the skb to the caller as if classification had\npassed. The only qdisc that wires up qevents today is RED, via three call sites\n(qe_mark on RED_PROB_MARK/HARD_MARK, qe_early_drop on congestion_drop)\nred_enqueue() was continuing to operate on an skb it no longer owns  in this\ncase -- enqueueing it, dropping it, or updating statistics. Resulting in a UAF.\n\n  tc qdisc add dev eth0 root handle 1: red ... qevent early_drop block 10\n  tc filter add block 10 ... action ct\n\n  (with ct defrag enabled and traffic that produces out-of-order\n  fragments, e.g. a fragmented UDP stream)\n\nHandle TC_ACT_CONSUMED in tcf_qevent_handle() the same way the ingress\nand egress fast paths do: treat it as stolen and return NULL without\ntouching the skb. Unlike the TC_ACT_STOLEN case, the skb must not be\ndropped/freed here, as it is no longer owned by us.","publishedAt":"2026-07-26T06:28:42.970Z","updatedAt":"2026-10-19T20:48:38.296Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"172ba7d46c202e679f3ccb10264c67416aaeb1c4","status":"affected","lessThan":"5ed3d6f85991656667059d3fa5a1d683ac58c447","versionType":"git"},{"version":"0b5b831122fc3789fff75be433ba3e4dd7b779d4","status":"affected","lessThan":"f42e8134a3a1074b834a574d404352f867ba994a","versionType":"git"},{"version":"73f7da5fd124f2cda9161e2e46114915e6e82e97","status":"affected","lessThan":"447d493034a9cf7bf13a2abac86d0573d907ec2f","versionType":"git"},{"version":"3f14b377d01d8357eba032b4cabc8c1149b458b6","status":"affected","lessThan":"e1270e69dcf2c3512c453484178f2e9dc0db3f05","versionType":"git"},{"version":"3f14b377d01d8357eba032b4cabc8c1149b458b6","status":"affected","lessThan":"2140c2f3f2e7b066e1ae616ede8856cafd8015e9","versionType":"git"},{"version":"3f14b377d01d8357eba032b4cabc8c1149b458b6","status":"affected","lessThan":"e28aedab9488343924d227b5a896faed67ce84d5","versionType":"git"},{"version":"3f14b377d01d8357eba032b4cabc8c1149b458b6","status":"affected","lessThan":"a8a02897f2b479127db261de05cbf0c28b98d159","versionType":"git"},{"version":"f5346df0591d10bc948761ca854b1fae6d2ef441","status":"affected","versionType":"git"},{"version":"5.15.148","status":"affected","lessThan":"5.15.212","versionType":"semver"},{"version":"6.1.75","status":"affected","lessThan":"6.1.178","versionType":"semver"},{"version":"6.6.14","status":"affected","lessThan":"6.6.145","versionType":"semver"},{"version":"6.7.2","status":"affected","lessThan":"6.8","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/cls_api.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.8","versionType":"semver"},{"version":"5.15.212","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/cls_api.c"]}],"references":["https://git.kernel.org/stable/c/5ed3d6f85991656667059d3fa5a1d683ac58c447","https://git.kernel.org/stable/c/f42e8134a3a1074b834a574d404352f867ba994a","https://git.kernel.org/stable/c/447d493034a9cf7bf13a2abac86d0573d907ec2f","https://git.kernel.org/stable/c/e1270e69dcf2c3512c453484178f2e9dc0db3f05","https://git.kernel.org/stable/c/2140c2f3f2e7b066e1ae616ede8856cafd8015e9","https://git.kernel.org/stable/c/e28aedab9488343924d227b5a896faed67ce84d5","https://git.kernel.org/stable/c/a8a02897f2b479127db261de05cbf0c28b98d159"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64530.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64530","state":"PUBLISHED","datePublished":"2026-07-26T06:28:42.970Z","dateUpdated":"2026-10-19T20:48:38.296Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.794Z"},"containers":{"cna":{"title":"net/sched: cls_api: Handle TC_ACT_CONSUMED in tcf_qevent_handle","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_api: Handle TC_ACT_CONSUMED in tcf_qevent_handle\n\ntcf_classify() can return TC_ACT_CONSUMED while the skb is held by the\ndefragmentation engine (e.g. act_ct on out-of-order fragments). When\nthat happens the skb is no longer owned by the caller and must not be\ntouched again.\n\ntcf_qevent_handle() did not handle TC_ACT_CONSUMED: it fell through the\nswitch and returned the skb to the caller as if classification had\npassed. The only qdisc that wires up qevents today is RED, via three call sites\n(qe_mark on RED_PROB_MARK/HARD_MARK, qe_early_drop on congestion_drop)\nred_enqueue() was continuing to operate on an skb it no longer owns  in this\ncase -- enqueueing it, dropping it, or updating statistics. Resulting in a UAF.\n\n  tc qdisc add dev eth0 root handle 1: red ... qevent early_drop block 10\n  tc filter add block 10 ... action ct\n\n  (with ct defrag enabled and traffic that produces out-of-order\n  fragments, e.g. a fragmented UDP stream)\n\nHandle TC_ACT_CONSUMED in tcf_qevent_handle() the same way the ingress\nand egress fast paths do: treat it as stolen and return NULL without\ntouching the skb. Unlike the TC_ACT_STOLEN case, the skb must not be\ndropped/freed here, as it is no longer owned by us."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"172ba7d46c202e679f3ccb10264c67416aaeb1c4","status":"affected","lessThan":"5ed3d6f85991656667059d3fa5a1d683ac58c447","versionType":"git"},{"version":"0b5b831122fc3789fff75be433ba3e4dd7b779d4","status":"affected","lessThan":"f42e8134a3a1074b834a574d404352f867ba994a","versionType":"git"},{"version":"73f7da5fd124f2cda9161e2e46114915e6e82e97","status":"affected","lessThan":"447d493034a9cf7bf13a2abac86d0573d907ec2f","versionType":"git"},{"version":"3f14b377d01d8357eba032b4cabc8c1149b458b6","status":"affected","lessThan":"e1270e69dcf2c3512c453484178f2e9dc0db3f05","versionType":"git"},{"version":"3f14b377d01d8357eba032b4cabc8c1149b458b6","status":"affected","lessThan":"2140c2f3f2e7b066e1ae616ede8856cafd8015e9","versionType":"git"},{"version":"3f14b377d01d8357eba032b4cabc8c1149b458b6","status":"affected","lessThan":"e28aedab9488343924d227b5a896faed67ce84d5","versionType":"git"},{"version":"3f14b377d01d8357eba032b4cabc8c1149b458b6","status":"affected","lessThan":"a8a02897f2b479127db261de05cbf0c28b98d159","versionType":"git"},{"version":"f5346df0591d10bc948761ca854b1fae6d2ef441","status":"affected","versionType":"git"},{"version":"5.15.148","status":"affected","lessThan":"5.15.212","versionType":"semver"},{"version":"6.1.75","status":"affected","lessThan":"6.1.178","versionType":"semver"},{"version":"6.6.14","status":"affected","lessThan":"6.6.145","versionType":"semver"},{"version":"6.7.2","status":"affected","lessThan":"6.8","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/cls_api.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.8","versionType":"semver"},{"version":"5.15.212","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/cls_api.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/5ed3d6f85991656667059d3fa5a1d683ac58c447"},{"url":"https://git.kernel.org/stable/c/f42e8134a3a1074b834a574d404352f867ba994a"},{"url":"https://git.kernel.org/stable/c/447d493034a9cf7bf13a2abac86d0573d907ec2f"},{"url":"https://git.kernel.org/stable/c/e1270e69dcf2c3512c453484178f2e9dc0db3f05"},{"url":"https://git.kernel.org/stable/c/2140c2f3f2e7b066e1ae616ede8856cafd8015e9"},{"url":"https://git.kernel.org/stable/c/e28aedab9488343924d227b5a896faed67ce84d5"},{"url":"https://git.kernel.org/stable/c/a8a02897f2b479127db261de05cbf0c28b98d159"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - On a transparent bridge or traffic-shaping gateway configured with the RED qevent and act_ct, unauthenticated remote IP fragments reach red_enqueue() through normal receive, bridge-forwarding, and egress-qdisc processing. No local netlink access is required to trigger the deployed configuration.\nAC:L - The attacker controls fragment contents and ordering and can drive RED into deterministic hard-mark or drop conditions with sustained traffic. No race or condition outside the attacker's control must be won.\nPR:N - CAP_NET_ADMIN is required to create the vulnerable configuration, but a remote attacker sending fragments through an already configured appliance needs no privileges or authentication. Local triggering is also possible with namespaced CAP_NET_ADMIN.\nUI:N - Triggering requires only attacker-generated fragmented traffic and does not depend on a victim performing any action.\nS:U - The corruption occurs within the host kernel and compromises resources governed by that same security authority. This remains unchanged scope even when used for namespace escape or kernel privilege escalation.\nC:H - The reclaimable sk_buff use-after-free and corrupted defragmentation-tree links can be leveraged through attacker-controlled network heap spraying to disclose arbitrary kernel memory.\nI:H - RED overwrites linkage fields that overlap the defragmentation RB node and may free the object while it remains referenced, enabling subsequent writes through freed or attacker-reclaimed kernel objects and potential code execution.\nA:H - The dangling fragment-tree entry can cause immediate or deferred use-after-free, double-free, invalid tree operations, and kernel panic when another fragment arrives or the queue expires. The attacker can trigger this repeatedly with fragmented traffic."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:57:07.900Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.148","versionEndExcluding":"5.15.212"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.75","versionEndExcluding":"6.1.178"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.14","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"7.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-64530","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:41:44.353854Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","lang":"en","type":"CWE","description":"CWE-416 Use After Free"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:48:38.296Z"}}]}}}