CVE-2026-72019 (GCVE-0-2026-72019)
Vulnerability from cvelistv5
Published
2026-08-15 05:51
Modified
2026-08-19 16:35
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
macsec: don't read an unset MAC header in macsec_encrypt()
macsec_encrypt() reads the Ethernet header via eth_hdr(skb)
(skb->head + skb->mac_header) to memmove() the 12 source/destination MAC
bytes forward and make room for the SecTAG.
On the AF_PACKET SOCK_RAW + PACKET_QDISC_BYPASS transmit path the skb
reaches the macsec ndo_start_xmit() with the MAC header unset, so
eth_hdr(skb) resolves to skb->head + (u16)~0 and the read is out of
bounds: a 12-byte heap over-read that is also emitted on the wire as the
frame's outer source/destination MAC. KASAN reports a slab-out-of-bounds
read in macsec_start_xmit() on 6.0; on current mainline a CONFIG_DEBUG_NET
build flags it as an unset mac header in skb_mac_header().
On the TX path the L2 header is at skb->data, so use skb_eth_hdr(), added
by commit 96cc4b69581d ("macvlan: do not assume mac_header is set in
macvlan_broadcast()") for exactly this purpose.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: c09440f7dcb304002dfced8c0fea289eb25f2da0 Version: c09440f7dcb304002dfced8c0fea289eb25f2da0 Version: c09440f7dcb304002dfced8c0fea289eb25f2da0 Version: c09440f7dcb304002dfced8c0fea289eb25f2da0 Version: c09440f7dcb304002dfced8c0fea289eb25f2da0 Version: c09440f7dcb304002dfced8c0fea289eb25f2da0 Version: c09440f7dcb304002dfced8c0fea289eb25f2da0 Version: c09440f7dcb304002dfced8c0fea289eb25f2da0 |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/macsec.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"status": "affected",
"version": "c09440f7dcb304002dfced8c0fea289eb25f2da0",
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},
{
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{
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"product": "Linux",
"programFiles": [
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.6"
},
{
"lessThan": "4.6",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
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},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.6",
"vulnerable": true
},
{
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{
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},
{
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},
{
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{
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}
],
"negate": false,
"operator": "OR"
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}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmacsec: don\u0027t 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\u0027s 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."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.3,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H",
"version": "3.1"
},
"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\u0027s source/destination MAC fields, disclosing sensitive heap contents.\nI:L - The memmove in macsec_encrypt() overwrites the outgoing frame\u0027s 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-\u003ehead 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": {
"dateUpdated": "2026-08-19T16:35:53.169Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"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"
}
],
"title": "macsec: don\u0027t read an unset MAC header in macsec_encrypt()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-72019",
"datePublished": "2026-08-15T05:51:46.014Z",
"dateReserved": "2026-08-09T03:40:39.900Z",
"dateUpdated": "2026-08-19T16:35:53.169Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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