{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64530", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.794Z", "datePublished": "2026-07-26T06:28:42.970Z", "dateUpdated": "2026-08-17T04:57:07.900Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:57:07.900Z" }, "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." } ], "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sched/cls_api.c" ], "versions": [ { "version": "172ba7d46c202e679f3ccb10264c67416aaeb1c4", "lessThan": "5ed3d6f85991656667059d3fa5a1d683ac58c447", "status": "affected", "versionType": "git" }, { "version": "0b5b831122fc3789fff75be433ba3e4dd7b779d4", "lessThan": "f42e8134a3a1074b834a574d404352f867ba994a", "status": "affected", "versionType": "git" }, { "version": "73f7da5fd124f2cda9161e2e46114915e6e82e97", "lessThan": "447d493034a9cf7bf13a2abac86d0573d907ec2f", "status": "affected", "versionType": "git" }, { "version": "3f14b377d01d8357eba032b4cabc8c1149b458b6", "lessThan": "e1270e69dcf2c3512c453484178f2e9dc0db3f05", "status": "affected", "versionType": "git" }, { "version": "3f14b377d01d8357eba032b4cabc8c1149b458b6", "lessThan": "2140c2f3f2e7b066e1ae616ede8856cafd8015e9", "status": "affected", "versionType": "git" }, { "version": "3f14b377d01d8357eba032b4cabc8c1149b458b6", "lessThan": "e28aedab9488343924d227b5a896faed67ce84d5", "status": "affected", "versionType": "git" }, { "version": "3f14b377d01d8357eba032b4cabc8c1149b458b6", "lessThan": "a8a02897f2b479127db261de05cbf0c28b98d159", "status": "affected", "versionType": "git" }, { "version": "f5346df0591d10bc948761ca854b1fae6d2ef441", "status": "affected", "versionType": "git" }, { "version": "5.15.148", "lessThan": "5.15.212", "status": "affected", "versionType": "semver" }, { "version": "6.1.75", "lessThan": "6.1.178", "status": "affected", "versionType": "semver" }, { "version": "6.6.14", "lessThan": "6.6.145", "status": "affected", "versionType": "semver" }, { "version": "6.7.2", "lessThan": "6.8", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sched/cls_api.c" ], "versions": [ { "version": "6.8", "status": "affected" }, { "version": "0", "lessThan": "6.8", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "5.15.148", "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" } ] } ] } ], "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" } ], "title": "net/sched: cls_api: Handle TC_ACT_CONSUMED in tcf_qevent_handle", "x_generator": { "engine": "bippy-1.2.0" } } } }