{"id":"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-\u003ehead + skb-\u003emac_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-\u003ehead + (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-\u003edata, so use skb_eth_hdr(), added\nby commit 96cc4b69581d (\"macvlan: do not assume mac_header is set in\nmacvlan_broadcast()\") for exactly this purpose.","modified":"2026-08-21T03:30:24.862240491Z","published":"2026-08-15T05:51:46.014Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72019.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2cf10d042562283ff4ae97c02d0993d4f1b5ea29"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3adea1b1c04b57e08a5c12a1f42483760581ce61"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b6cec6187b8632423cd99a94fd5e5ba165fa2a33"},{"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"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"c09440f7dcb304002dfced8c0fea289eb25f2da0"},{"fixed":"b6cec6187b8632423cd99a94fd5e5ba165fa2a33"},{"fixed":"3adea1b1c04b57e08a5c12a1f42483760581ce61"},{"fixed":"dc9ffa1905e72f026d080880a2e4cfc42aa91000"},{"fixed":"f21fa533a3ed15ada74106aac4b9ddd078fc6b7a"},{"fixed":"e17a42199824973cd8212e95b21ffadf4114a21b"},{"fixed":"2cf10d042562283ff4ae97c02d0993d4f1b5ea29"},{"fixed":"c39087ad0b97fc11a3b058dfc8db9fd370762cb9"},{"fixed":"f5089008f90c0a7c5520dff3934e0af00adf322d"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72019.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.6.0"},{"fixed":"5.10.265"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.216"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.178"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.145"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.97"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.40"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72019.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H"}]}