{"id":"CVE-2026-72019","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-72019","summary":"macsec: don't read an unset MAC header in macsec_encrypt()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmacsec: don't read an unset MAC header in macsec_encrypt()\n\nmacsec_encrypt() reads the Ethernet header via eth_hdr(skb)\n(skb->head + skb->mac_header) to memmove() the 12 source/destination MAC\nbytes forward and make room for the SecTAG.\n\nOn the AF_PACKET SOCK_RAW + PACKET_QDISC_BYPASS transmit path the skb\nreaches the macsec ndo_start_xmit() with the MAC header unset, so\neth_hdr(skb) resolves to skb->head + (u16)~0 and the read is out of\nbounds: a 12-byte heap over-read that is also emitted on the wire as the\nframe's outer source/destination MAC. KASAN reports a slab-out-of-bounds\nread in macsec_start_xmit() on 6.0; on current mainline a CONFIG_DEBUG_NET\nbuild flags it as an unset mac header in skb_mac_header().\n\nOn the TX path the L2 header is at skb->data, so use skb_eth_hdr(), added\nby commit 96cc4b69581d (\"macvlan: do not assume mac_header is set in\nmacvlan_broadcast()\") for exactly this purpose.","published":"2026-08-15T05:51:46.014Z","modified":"2026-08-18T03:56:36.235822882Z","cvss":{"score":7.3,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.1.178"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2cf10d042562283ff4ae97c02d0993d4f1b5ea29"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c39087ad0b97fc11a3b058dfc8db9fd370762cb9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/dc9ffa1905e72f026d080880a2e4cfc42aa91000"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e17a42199824973cd8212e95b21ffadf4114a21b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f21fa533a3ed15ada74106aac4b9ddd078fc6b7a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f5089008f90c0a7c5520dff3934e0af00adf322d"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72019.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72019"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-18T03:56:36.235822882Z"}}