{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74666", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.924Z", "datePublished": "2026-08-22T15:32:38.098Z", "dateUpdated": "2026-10-16T19:16:08.102Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-27T12:40:00.544Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npacket: synchronize pressure clearing with ring reconfiguration\n\npacket_set_ring() updates the RX ring state under sk_receive_queue.lock,\nbut used to publish the tpacket receive mode through po->prot_hook.func\nafter releasing that lock. packet_poll() and packet_recvmsg() can then\nrun the pressure clearing path after the ring has been cleared while\nstill seeing tpacket_rcv, causing __packet_rcv_has_room() to dereference\nstale or NULL ring storage.\n\nMove the existing receive hook assignment into the same\nsk_receive_queue.lock section as the ring state update. Keep the\nassignment otherwise unchanged, including on TX ring reconfiguration, to\navoid adding behavior changes that are not required for the fix.\n\nSerialize packet_recvmsg() pressure clearing with the same queue lock\nonly after PACKET_SOCK_PRESSURE has been observed. If the flag is clear\nand the socket has moved away from tpacket_rcv, packet_set_ring() has\nalready detached the socket and waited for synchronize_net(), so no new\npacket input can set the flag again.\n\npacket_poll() already holds sk_receive_queue.lock, so it uses the new\nunlocked helper directly." } ], "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" }, "scenarios": [ { "lang": "en", "value": "AV:L - The bug is hit only from local AF_PACKET syscalls—setsockopt(PACKET_RX_RING) racing poll(2)/recvmsg(2) pressure clearing in packet_poll()/packet_recvmsg()—not from remote packet receive paths like ksmbd, nfsd, or the TCP/IP stack.\nAC:L - The attacker controls both race sides: one thread polls/recvmsg while PACKET_SOCK_PRESSURE is set, another tears down the RX ring via PACKET_RX_RING; packet_set_ring()'s synchronize_net() window makes the stale tpacket_rcv vs NULL/freed pg_vec mismatch reliably winnable.\nPR:L - packet_create() requires ns_capable(net->user_ns, CAP_NET_RAW); unprivileged users obtain CAP_NET_RAW via user+network namespaces (unshare -Urn) or container defaults (Docker NET_RAW), without init-namespace root.\nUI:N - No victim action is required; the attacker creates the AF_PACKET socket, configures the mmap RX ring, fills it to set PACKET_SOCK_PRESSURE, and races ring teardown against its own poll/recvmsg calls.\nS:U - Stale/NULL ring dereferences corrupt kernel heap state on the same host; this is standard kernel memory corruption within one security authority, not a VM escape, IOMMU bypass, or other cross-boundary scope change.\nC:H - __packet_rcv_has_room() follows tpacket_rcv and dereferences rb->pg_vec or prb_bdqc block pointers after packet_set_ring() cleared/freed the ring, yielding NULL-dereference or use-after-free reads of ring metadata and mmap-backed pages.\nI:H - Freed ring storage and stale prb_bdqc/pkbdq pointers remain attacker-influenced through mmap and concurrent ring operations, providing a controllable kernel heap use-after-free write primitive typical of AF_PACKET ring reconfiguration races.\nA:H - NULL pg_vec indexing in packet_lookup_frame() or stale block access in prb_lookup_block() from the pressure-clearing path causes an immediate kernel oops/panic, giving any qualifying local attacker repeatable host-wide denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/packet/af_packet.c" ], "versions": [ { "version": "2ccdbaa6d55b0656244ba57c4b56765a0af76c0a", "lessThan": "bf3c8e86bc8ad111be3f3136125e255344bcb3da", "status": "affected", "versionType": "git" }, { "version": "2ccdbaa6d55b0656244ba57c4b56765a0af76c0a", "lessThan": "8cfb2e71926a682f36c4240067d424074dd8f70f", "status": "affected", "versionType": "git" }, { "version": "2ccdbaa6d55b0656244ba57c4b56765a0af76c0a", "lessThan": "f015c9de92b731814059a343b765c60c0196225c", "status": "affected", "versionType": "git" }, { "version": "2ccdbaa6d55b0656244ba57c4b56765a0af76c0a", "lessThan": "cf8189b82bb93f219ab740e0346c919ad65ada62", "status": "affected", "versionType": "git" }, { "version": "2ccdbaa6d55b0656244ba57c4b56765a0af76c0a", "lessThan": "ad740b4990347521f0db260d381f9f74e7b340ba", "status": "affected", "versionType": "git" }, { "version": "2ccdbaa6d55b0656244ba57c4b56765a0af76c0a", "lessThan": "2c7b5eb87b2b288cdbde825f21d2b83b2f5da747", "status": "affected", "versionType": "git" }, { "version": "2ccdbaa6d55b0656244ba57c4b56765a0af76c0a", "lessThan": "a08196c3cc105947746ec21309edfbb60275fcdb", "status": "affected", "versionType": "git" }, { "version": "2ccdbaa6d55b0656244ba57c4b56765a0af76c0a", "lessThan": "1a35da325cac4d5bcad76a2aa943408a6f1d9000", "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/packet/af_packet.c" ], "versions": [ { "version": "4.2", "status": "affected" }, { "version": "0", "lessThan": "4.2", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.267", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.218", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.185", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.152", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.104", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.45", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.9", "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": "4.2", "versionEndExcluding": "5.10.267" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "5.15.218" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.1.185" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.6.152" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.12.104" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.18.45" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "7.1.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/bf3c8e86bc8ad111be3f3136125e255344bcb3da" }, { "url": "https://git.kernel.org/stable/c/8cfb2e71926a682f36c4240067d424074dd8f70f" }, { "url": "https://git.kernel.org/stable/c/f015c9de92b731814059a343b765c60c0196225c" }, { "url": "https://git.kernel.org/stable/c/cf8189b82bb93f219ab740e0346c919ad65ada62" }, { "url": "https://git.kernel.org/stable/c/ad740b4990347521f0db260d381f9f74e7b340ba" }, { "url": "https://git.kernel.org/stable/c/2c7b5eb87b2b288cdbde825f21d2b83b2f5da747" }, { "url": "https://git.kernel.org/stable/c/a08196c3cc105947746ec21309edfbb60275fcdb" }, { "url": "https://git.kernel.org/stable/c/1a35da325cac4d5bcad76a2aa943408a6f1d9000" } ], "title": "packet: synchronize pressure clearing with ring reconfiguration", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-74666", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:14:12.266180Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:16:08.102Z" } } ] } }