{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74668", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.924Z", "datePublished": "2026-08-22T15:32:39.583Z", "dateUpdated": "2026-10-16T19:16:08.423Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-27T12:40:01.903Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npacket: use consistent hard_header_len in TX_RING send path\n\ntpacket_snd() reads dev->hard_header_len independently for skb\nallocation and header construction in tpacket_fill_skb(). Concurrent\nnetdevice reconfiguration can therefore make the reserved headroom\nsmaller than the amount later pushed, or make copylen - hard_header_len\nnegative.\n\nSnapshot hard_header_len once before processing ring frames and use it\nfor the frame limit, headroom allocation, copy length, and skb\nconstruction. Pass the snapshot to tpacket_fill_skb().\n\nThe separate SOCK_DGRAM consistency problem between hard_header_len and\nheader_ops->create is not addressed here." } ], "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 flaw is reached only via local syscalls on an AF_PACKET socket with PACKET_TX_RING configured (sendmsg on mmap ring frames); it is not triggered by processing remotely received network traffic.\nAC:L - An attacker can open the TX_RING socket and concurrently reconfigure the bound netdev (e.g., VLAN/bonding/macvlan changes) in a user+network namespace, controlling both sides of the hard_header_len race without depending on external timing.\nPR:L - Exploitation requires CAP_NET_RAW to create AF_PACKET sockets and CAP_NET_ADMIN to change netdev hard_header_len; both are obtainable by an unprivileged user inside a user namespace without init-namespace root.\nUI:N - No victim interaction is required; the attacker triggers the bug using their own packet socket, TX_RING, and netdev reconfiguration threads.\nS:U - Impact is kernel heap corruption and local privilege escalation within the same kernel security domain; it does not constitute a VM escape, sandbox breakout, or IOMMU boundary bypass.\nC:H - Racing hard_header_len can make skb_push exceed reserved headroom or skb_put use a negative length (huge unsigned), and subsequent skb_store_bits writes before skb->head or far past skb->tail, corrupting adjacent slab objects and enabling kernel memory disclosure.\nI:H - Inconsistent hard_header_len between skb allocation and tpacket_fill_skb causes out-of-bounds linear expansion and data writes in the skb buffer, yielding heap corruption primitives suitable for control-flow hijacking and local privilege escalation.\nA:H - Corrupted skb_push/put operations invoke skb_under_panic or skb_over_panic (BUG), causing kernel oops/panic and reliable denial of service even when exploitation is not completed." } ] } ], "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": "69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1", "lessThan": "9c7e8ff48c377bef18c3d178748aea0575b69ede", "status": "affected", "versionType": "git" }, { "version": "69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1", "lessThan": "2a73b2c37ee3060a880b53cd24783d93fc7be5f8", "status": "affected", "versionType": "git" }, { "version": "69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1", "lessThan": "e79f59a8527a49078cfaf8fe8fb5fcefc20c76d2", "status": "affected", "versionType": "git" }, { "version": "69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1", "lessThan": "d85d2fd54e901637c81d847811e03c662aee13cd", "status": "affected", "versionType": "git" }, { "version": "69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1", "lessThan": "016763e829cac37b3234eace86fd0a4c560de4a7", "status": "affected", "versionType": "git" }, { "version": "69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1", "lessThan": "27e068d1b35dbec10a3cf268887c94407be4badc", "status": "affected", "versionType": "git" }, { "version": "69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1", "lessThan": "d48ea5c9c4c34dc0df621f0e39ed3a16b644621a", "status": "affected", "versionType": "git" }, { "version": "69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1", "lessThan": "21b5953e7494c16a42e6cd8cf110e18d13ae4a6b", "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": "2.6.31", "status": "affected" }, { "version": "0", "lessThan": "2.6.31", "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": "2.6.31", "versionEndExcluding": "5.10.267" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "5.15.218" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "6.1.185" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "6.6.152" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "6.12.104" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "6.18.45" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "7.1.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/9c7e8ff48c377bef18c3d178748aea0575b69ede" }, { "url": "https://git.kernel.org/stable/c/2a73b2c37ee3060a880b53cd24783d93fc7be5f8" }, { "url": "https://git.kernel.org/stable/c/e79f59a8527a49078cfaf8fe8fb5fcefc20c76d2" }, { "url": "https://git.kernel.org/stable/c/d85d2fd54e901637c81d847811e03c662aee13cd" }, { "url": "https://git.kernel.org/stable/c/016763e829cac37b3234eace86fd0a4c560de4a7" }, { "url": "https://git.kernel.org/stable/c/27e068d1b35dbec10a3cf268887c94407be4badc" }, { "url": "https://git.kernel.org/stable/c/d48ea5c9c4c34dc0df621f0e39ed3a16b644621a" }, { "url": "https://git.kernel.org/stable/c/21b5953e7494c16a42e6cd8cf110e18d13ae4a6b" } ], "title": "packet: use consistent hard_header_len in TX_RING send path", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-74668", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:14:18.018901Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:16:08.423Z" } } ] } }