{"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":"2026-08-27T12:40:01.903Z"},"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"}}}}