{"cve":"CVE-2026-74582","nvd":{"published":"2026-08-21T17:16:44.507","modified":"2026-10-16T20:17:40.100","status":"Received","description":"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 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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":[],"references":["https://git.kernel.org/stable/c/03390aa32e669cc4ecd7d34108e2e1afc13d689d","https://git.kernel.org/stable/c/142e287b3a25cfe909215177c23243e7fc5ae2b1","https://git.kernel.org/stable/c/5bb10753d428aadfc356a2bfe9acea09c82a62ec","https://git.kernel.org/stable/c/78a47127e33c340bc6d38dcc4552a094b4f5cc77","https://git.kernel.org/stable/c/9052756290962ffb9a661bcf319e92dedaaedfed"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:49:38.260478770+00:00"},"epss":{"cve":"CVE-2026-74582","score":0.0012,"percentile":0.0184,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}