{"id":"CVE-2026-72019","title":"macsec: don't read an unset MAC header in macsec_encrypt()","summary":"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 1…","severity":"high","cvss":7.3,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < b6cec6187b8632423cd99a94fd5e5ba165fa2a33","Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < 3adea1b1c04b57e08a5c12a1f42483760581ce61","Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < dc9ffa1905e72f026d080880a2e4cfc42aa91000","Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < f21fa533a3ed15ada74106aac4b9ddd078fc6b7a","Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < e17a42199824973cd8212e95b21ffadf4114a21b","Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < 2cf10d042562283ff4ae97c02d0993d4f1b5ea29","Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < c39087ad0b97fc11a3b058dfc8db9fd370762cb9","Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < f5089008f90c0a7c5520dff3934e0af00adf322d","Linux 4.6"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-16T15:50:03.923013Z"},"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:53:16.257Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72019","references":[{"url":"https://git.kernel.org/stable/c/b6cec6187b8632423cd99a94fd5e5ba165fa2a33"},{"url":"https://git.kernel.org/stable/c/3adea1b1c04b57e08a5c12a1f42483760581ce61"},{"url":"https://git.kernel.org/stable/c/dc9ffa1905e72f026d080880a2e4cfc42aa91000"},{"url":"https://git.kernel.org/stable/c/f21fa533a3ed15ada74106aac4b9ddd078fc6b7a"},{"url":"https://git.kernel.org/stable/c/e17a42199824973cd8212e95b21ffadf4114a21b"},{"url":"https://git.kernel.org/stable/c/2cf10d042562283ff4ae97c02d0993d4f1b5ea29"},{"url":"https://git.kernel.org/stable/c/c39087ad0b97fc11a3b058dfc8db9fd370762cb9"},{"url":"https://git.kernel.org/stable/c/f5089008f90c0a7c5520dff3934e0af00adf322d"}],"tags":["cve.org"],"epss":0.00172,"epssPercentile":0.06162,"ingestedAt":"2026-10-16T17:24:46.870Z","slug":"CVE-2026-72019","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < b6cec6187b8632423cd99a94fd5e5ba165fa2a33`\n- `Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < 3adea1b1c04b57e08a5c12a1f42483760581ce61`\n- `Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < dc9ffa1905e72f026d080880a2e4cfc42aa91000`\n- `Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < f21fa533a3ed15ada74106aac4b9ddd078fc6b7a`\n- `Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < e17a42199824973cd8212e95b21ffadf4114a21b`\n- `Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < 2cf10d042562283ff4ae97c02d0993d4f1b5ea29`\n- `Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < c39087ad0b97fc11a3b058dfc8db9fd370762cb9`\n- `Linux >= c09440f7dcb304002dfced8c0fea289eb25f2da0 < f5089008f90c0a7c5520dff3934e0af00adf322d`\n- `Linux 4.6`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":40,"depthScoreParts":{"impact":40.2,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}