{"id":"CVE-2026-80731","summary":"net: remove CAP_SYS_RAWIO zero-padding in dev_validate_header","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: remove CAP_SYS_RAWIO zero-padding in dev_validate_header\n\ndev_validate_header() reads dev-\u003ehard_header_len directly when\nzero-padding short link layer headers for CAP_SYS_RAWIO holders:\n\n    if (capable(CAP_SYS_RAWIO)) {\n        memset(ll_header + len, 0, dev-\u003ehard_header_len - len);\n        return true;\n    }\n\nPacket send paths call dev_validate_header() on skbs whose headroom was\nallocated from an earlier hard_header_len read. If the device is\nreconfigured so that dev-\u003ehard_header_len increases before validation,\nthe memset writes past the reserved buffer, an out-of-bounds write.\n\nThis out-of-bounds write is masked in some SOCK_RAW paths today because\nthe same concurrent increase can first make skb_push() exceed the\nreserved headroom and trigger skb_under_panic(). Remove the zero-padding\nbranch before making those hard_header_len reads consistent, so the\nsnapshot fixes do not turn a loud panic into a silent overwrite.\n\nThis path is only reached for variable length L2 protocols, where\nlen \u003c hard_header_len but len \u003e= min_header_len. No remaining in-tree\nvariable length L2 protocol implements header_ops-\u003evalidate, and the\nCAP_SYS_RAWIO bypass that zero-pads and accepts short headers has no\nreal value beyond allowing testing of intentionally malformed input.\n\nDrop the CAP_SYS_RAWIO branch. The remaining reads of\ndev-\u003ehard_header_len in dev_validate_header() are comparisons only and\nhave no memory safety impact.","modified":"2026-10-28T02:30:42.095806730Z","published":"2026-09-03T08:21:48.924Z","related":["SUSE-SU-2026:23881-1","SUSE-SU-2026:23887-1","SUSE-SU-2026:23897-1","SUSE-SU-2026:23902-1","SUSE-SU-2026:24181-1","SUSE-SU-2026:24182-1","SUSE-SU-2026:24315-1","SUSE-SU-2026:24316-1","SUSE-SU-2026:4640-1","SUSE-SU-2026:4687-1","SUSE-SU-2026:4706-1","openSUSE-SU-2026:21910-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80731.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/3b9a324e646d3657a8d9806dfbfe4f3e4066e882"},{"type":"WEB","url":"https://git.kernel.org/stable/c/53fd7f912c0877647d6a1e1877f5ea8535ee0b4a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/74e035f07f53feca09e2352e77fccb09cad5e208"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8fc9816404166a90ed8d544dc52482fafffb6d9f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/99df6b7a713f96eda206680d100b76e15f9d9b69"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b0f92a5731dc82556a9ae005cc35f71ab136307b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/dbb30dc943a93e083f1e531bfdc6779e57de40d0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fa6d98dd925e72fc028b26a0cbbff9d2f0601ff6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fc902f52a02298c7432b2334c0c82a2885a1a8b6"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80731.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80731"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"b5518429e70cd783b8ca52335456172c1a0589f6"},{"fixed":"53fd7f912c0877647d6a1e1877f5ea8535ee0b4a"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"2793a23aacbd754dbbb5cb75093deb7e4103bace"},{"fixed":"fa6d98dd925e72fc028b26a0cbbff9d2f0601ff6"},{"fixed":"8fc9816404166a90ed8d544dc52482fafffb6d9f"},{"fixed":"b0f92a5731dc82556a9ae005cc35f71ab136307b"},{"fixed":"99df6b7a713f96eda206680d100b76e15f9d9b69"},{"fixed":"74e035f07f53feca09e2352e77fccb09cad5e208"},{"fixed":"dbb30dc943a93e083f1e531bfdc6779e57de40d0"},{"fixed":"fc902f52a02298c7432b2334c0c82a2885a1a8b6"},{"fixed":"3b9a324e646d3657a8d9806dfbfe4f3e4066e882"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3.2.80"},{"fixed":"3.2.81"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3.16.36"},{"fixed":"3.17"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4.1.28"},{"fixed":"4.2"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4.4.8"},{"fixed":"4.5"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4.5.2"},{"fixed":"4.6"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"f58a6c08ebdfa978178bbca78c2ba744a2665912"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"1df16498dfd0d5a129bdf2982d9a08df73e8923d"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"8b8d278aa4de9335682bbd4a3bb619af015c859e"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6804052fa9d86e9a512c88b24a5debbfc1a490fc"}]}],"versions":["v3.2.80","v3.16.85","v3.16.84","v3.16.83","v3.16.82","v3.16.81","v3.16.80","v3.16.79","v3.16.78","v3.16.77","v3.16.76","v3.16.75","v3.16.74","v3.16.73","v3.16.72","v3.16.71","v3.16.70","v3.16.69","v3.16.68","v3.16.67","v3.16.66","v3.16.65","v3.16.64","v3.16.63","v3.16.62","v3.16.61","v3.16.60","v3.16.59","v3.16.58","v3.16.57","v3.16.56","v3.16.55","v3.16.54","v3.16.53","v3.16.52","v3.16.51","v3.16.50","v3.16.49","v3.16.48","v3.16.47","v3.16.46","v3.16.45","v3.16.44","v3.16.43","v3.16.42","v3.16.41","v3.16.40","v3.16.39","v3.16.38","v3.16.37","v3.16.36","v4.1.52","v4.1.51","v4.1.50","v4.1.49","v4.1.48","v4.1.47","v4.1.46","v4.1.45","v4.1.44","v4.1.43","v4.1.42","v4.1.41","v4.1.40","v4.1.39","v4.1.38","v4.1.37","v4.1.36","v4.1.35","v4.1.34","v4.1.33","v4.1.32","v4.1.31","v4.1.30","v4.1.29","v4.1.28","v4.4.302","v4.4.301","v4.4.300","v4.4.299","v4.4.298","v4.4.297","v4.4.296","v4.4.295","v4.4.294","v4.4.293","v4.4.292","v4.4.291","v4.4.290","v4.4.289","v4.4.288","v4.4.287","v4.4.286","v4.4.285","v4.4.284","v4.4.283","v4.4.282","v4.4.281","v4.4.280","v4.4.279","v4.4.278","v4.4.277","v4.4.276","v4.4.275","v4.4.274","v4.4.273",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