High 7.3Published Aug 15, 2026

CVE-2026-72019macsec: don't read an unset MAC header in macsec_encrypt()

Updated under an hour ago (Oct 27, 2026, 10:10 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 7.3 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H
Weakness (CWE): CWE-125
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Received
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from c09440f7dcb304002dfced8c0fea289eb25f2da0 before b6cec6187b8632423cd99a94fd5e5ba165fa2a33; from c09440f7dcb304002dfced8c0fea289eb25f2da0 before 3adea1b1c04b57e08a5c12a1f42483760581ce61; from c09440f7dcb304002dfced8c0fea289eb25f2da0 before dc9ffa1905e72f026d080880a2e4cfc42aa91000; from c09440f7dcb304002dfced8c0fea289eb25f2da0 before f21fa533a3ed15ada74106aac4b9ddd078fc6b7a; from c09440f7dcb304002dfced8c0fea289eb25f2da0 before e17a42199824973cd8212e95b21ffadf4114a21b; from c09440f7dcb304002dfced8c0fea289eb25f2da0 before 2cf10d042562283ff4ae97c02d0993d4f1b5ea29; from c09440f7dcb304002dfced8c0fea289eb25f2da0 before c39087ad0b97fc11a3b058dfc8db9fd370762cb9; from c09440f7dcb304002dfced8c0fea289eb25f2da0 before f5089008f90c0a7c5520dff3934e0af00adf322d	CNA record

References

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

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.