{"id":"CVE-2026-72019","state":"PUBLISHED","title":"macsec: don't read an unset MAC header in macsec_encrypt()","description":"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.","publishedAt":"2026-08-15T05:51:46.014Z","updatedAt":"2026-10-19T21:19:23.088Z","severity":{"score":7.3,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"b6cec6187b8632423cd99a94fd5e5ba165fa2a33","versionType":"git"},{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"3adea1b1c04b57e08a5c12a1f42483760581ce61","versionType":"git"},{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"dc9ffa1905e72f026d080880a2e4cfc42aa91000","versionType":"git"},{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"f21fa533a3ed15ada74106aac4b9ddd078fc6b7a","versionType":"git"},{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"e17a42199824973cd8212e95b21ffadf4114a21b","versionType":"git"},{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"2cf10d042562283ff4ae97c02d0993d4f1b5ea29","versionType":"git"},{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"c39087ad0b97fc11a3b058dfc8db9fd370762cb9","versionType":"git"},{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"f5089008f90c0a7c5520dff3934e0af00adf322d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/macsec.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.6","versionType":"semver"},{"version":"5.10.265","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.216","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/macsec.c"]}],"references":["https://git.kernel.org/stable/c/b6cec6187b8632423cd99a94fd5e5ba165fa2a33","https://git.kernel.org/stable/c/3adea1b1c04b57e08a5c12a1f42483760581ce61","https://git.kernel.org/stable/c/dc9ffa1905e72f026d080880a2e4cfc42aa91000","https://git.kernel.org/stable/c/f21fa533a3ed15ada74106aac4b9ddd078fc6b7a","https://git.kernel.org/stable/c/e17a42199824973cd8212e95b21ffadf4114a21b","https://git.kernel.org/stable/c/2cf10d042562283ff4ae97c02d0993d4f1b5ea29","https://git.kernel.org/stable/c/c39087ad0b97fc11a3b058dfc8db9fd370762cb9","https://git.kernel.org/stable/c/f5089008f90c0a7c5520dff3934e0af00adf322d"],"weaknesses":["CWE-125"],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/72xxx/CVE-2026-72019.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72019","state":"PUBLISHED","datePublished":"2026-08-15T05:51:46.014Z","dateUpdated":"2026-10-19T21:19:23.088Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-09T03:40:39.900Z"},"containers":{"cna":{"title":"macsec: don't read an unset MAC header in macsec_encrypt()","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"b6cec6187b8632423cd99a94fd5e5ba165fa2a33","versionType":"git"},{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"3adea1b1c04b57e08a5c12a1f42483760581ce61","versionType":"git"},{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"dc9ffa1905e72f026d080880a2e4cfc42aa91000","versionType":"git"},{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"f21fa533a3ed15ada74106aac4b9ddd078fc6b7a","versionType":"git"},{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"e17a42199824973cd8212e95b21ffadf4114a21b","versionType":"git"},{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"2cf10d042562283ff4ae97c02d0993d4f1b5ea29","versionType":"git"},{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"c39087ad0b97fc11a3b058dfc8db9fd370762cb9","versionType":"git"},{"version":"c09440f7dcb304002dfced8c0fea289eb25f2da0","status":"affected","lessThan":"f5089008f90c0a7c5520dff3934e0af00adf322d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/macsec.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.6","versionType":"semver"},{"version":"5.10.265","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.216","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/macsec.c"]}],"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"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H","baseScore":7.3,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bug is reached only via local AF_PACKET SOCK_RAW transmit with PACKET_QDISC_BYPASS to a macsec netdev; it is a TX-only ndo_start_xmit path, not reachable from remote network packet reception.\nAC:L - An attacker fully controls the trigger: create a raw packet socket with a specific ethertype, enable PACKET_QDISC_BYPASS, and send a frame on a configured macsec interface with protect_frames enabled.\nPR:L - Exploitation requires CAP_NET_RAW for AF_PACKET and CAP_NET_ADMIN to create/configure a macsec netdev and TX SA keys; both are obtainable by an unprivileged user inside a user namespace with delegated capabilities.\nUI:N - No victim interaction is required; the attacker sends crafted frames directly through the vulnerable transmit path without any action from another user or administrator.\nS:U - Impact is confined to kernel heap disclosure and possible kernel crash on the same host; it does not cross a VM, container, or IOMMU security boundary to affect a separate authority.\nC:H - eth_hdr(skb) performs a 12-byte slab out-of-bounds heap read when mac_header is unset; the leaked kernel memory is copied into the transmitted frame's source/destination MAC fields, disclosing sensitive heap contents.\nI:L - The memmove in macsec_encrypt() overwrites the outgoing frame's 12-byte Ethernet addresses with leaked heap data, causing unauthorized modification of transmitted packet contents without arbitrary kernel memory writes.\nA:H - Reading from skb->head plus unset mac_header offset 65535 causes a slab out-of-bounds access that KASAN flags and can page-fault into a kernel oops or panic when macsec_encrypt() runs on affected builds."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-19T16:35:53.169Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"5.10.265"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"5.15.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"6.1.178"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-72019","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:50:03.923013Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","lang":"en","type":"CWE","description":"CWE-125 Out-of-bounds Read"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T21:19:23.088Z"}}]}}}