{"id":"CVE-2026-74582","title":"In the Linux kernel, the following vulnerability has been resolved:\n\npacket: use consistent hard_header_len in non-ring send paths\n\npacket_snd() reads dev->hard_header_len multiple times while allocating\nand constructing an skb","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\npacket: use consistent hard_header_len in non-ring send paths\n\npacket_snd() reads dev->hard_header_len multiple times while allocating\nand constructing an skb. Device r…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","published":"2026-08-21","updated":"2026-10-14","sourceUpdated":"2026-10-14T19:10:00.297","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-74582","references":[{"url":"https://git.kernel.org/stable/c/03390aa32e669cc4ecd7d34108e2e1afc13d689d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/142e287b3a25cfe909215177c23243e7fc5ae2b1","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5bb10753d428aadfc356a2bfe9acea09c82a62ec","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/78a47127e33c340bc6d38dcc4552a094b4f5cc77","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9052756290962ffb9a661bcf319e92dedaaedfed","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/91f041451f967cd87ed722a8f43c0b767a64f1a0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b06b6fce6d7deaf7238e09b48ce3b1125ff41acd","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bcd4df60ac9481b1ceffdfe5ec38fe51dcaae812","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.0012,"epssPercentile":0.01714,"ingestedAt":"2026-10-14T19:49:57.560Z","slug":"CVE-2026-74582","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\npacket: use consistent hard_header_len in non-ring send paths\n\npacket_snd() reads dev->hard_header_len multiple times while allocating\nand constructing an skb. Device reconfiguration can change this value\nconcurrently, for example through bonding device type changes.\n\nFor SOCK_RAW, packet_snd() can save a larger value in reserve and later\nallocate headroom using a smaller value. Moving skb->data back by reserve\nthen places it before skb->head, and the following copy from userspace can\nattempt an out-of-bounds write.\n\npacket_sendmsg_spkt() has the same issue because it calculates its\nreservation and header offset from separate reads before dropping the RCU\nread lock to allocate the skb.\n\nAdd LL_RESERVED_SPACE_EX() for callers that already saved a header length.\nRead hard_header_len once in packet_snd() and use it for allocation and\nconstruction. In packet_sendmsg_spkt(), preserve the allocation-time value\nthrough the device lookup retry.\n\nThe separate SOCK_DGRAM consistency problem between hard_header_len and\nheader_ops->create is not addressed here.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}