{"apiVersion":"1.0","identifier":"CVE-2026-74667","description":"In the Linux kernel, the following vulnerability has been resolved: net/packet: reset the MAC header on the packet-socket transmit path packet_parse_headers() resets the MAC header only for a SOCK_RAW frame whose socket did not bind a protocol. A protocol-bound SOCK_RAW socket, any SOCK_DGRAM frame, and the legacy SOCK_PACKET path therefore leave skb->mac_header unset here. For frames sent via __dev_queue_xmit() this is harmless: it resets the MAC header unconditionally. But the packet-socket PACKET_QDISC_BYPASS path uses dev_direct_xmit(), which does not, so the frame reaches ndo_start_xmit() with the MAC header unset. A driver that reads eth_hdr(skb) on transmit then dereferences skb->head + (u16)~0, an out-of-bounds access ~64 KiB past the head -- the same class fixed for one consumer in commit f5089008f90c (-macsec: do not read an unset MAC header in macsec_encrypt()-). packet_parse_headers() runs only on the transmit path, where skb->data points at the start of the L2 header for every packet-socket type regardless of its length: SOCK_RAW and SOCK_PACKET carry a user-supplied header and SOCK_DGRAM has one built by dev_hard_header(). Reset the MAC header unconditionally, mirroring __dev_queue_xmit(), so the frame is anchored on the bypass path too. Found by 0sec (https://0sec.ai) using automated source analysis; verified against source and matched to the macsec KASAN report in f5089008f90c. Compile-tested.","publishedAt":"2026-08-22T16:16:40","lastModifiedAt":"2026-08-25T06:18:48","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-74667","cvssScore":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","epssProbability":0.00136,"riskScore":0.79,"affectedProduct":"linux","affectedVersions":"unknown","vulnerabilityType":"Kernel","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-74667","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-74667","en":"https://www.redsauce.net/en/cves/CVE-2026-74667","fr":"https://www.redsauce.net/fr/cves/CVE-2026-74667","pt":"https://www.redsauce.net/pt/cves/CVE-2026-74667","de":"https://www.redsauce.net/de/cves/CVE-2026-74667","sk":"https://www.redsauce.net/sk/cves/CVE-2026-74667","el":"https://www.redsauce.net/el/cves/CVE-2026-74667"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-74667"}}