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CVE-2026-72019

macsec: don't read an unset MAC header in macsec_encrypt()

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.265, 5.15.216, 6.1.178, 6.6.145, 6.12.97, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • Linux Linux

    From c09440f7dcb304002dfced8c0fea289eb25f2da0 · fixed in b6cec6187b8632423cd99a94fd5e5ba165fa2a33; From c09440f7dcb304002dfced8c0fea289eb25f2da0 · fixed in 3adea1b1c04b57e08a5c12a1f42483760581ce61; From c09440f7dcb304002dfced8c0fea289eb25f2da0 · fixed in dc9ffa1905e72f026d080880a2e4cfc42aa91000; From c09440f7dcb304002dfced8c0fea289eb25f2da0 · fixed in f21fa533a3ed15ada74106aac4b9ddd078fc6b7a; From c09440f7dcb304002dfced8c0fea289eb25f2da0 · fixed in e17a42199824973cd8212e95b21ffadf4114a21b; From c09440f7dcb304002dfced8c0fea289eb25f2da0 · fixed in 2cf10d042562283ff4ae97c02d0993d4f1b5ea29; From c09440f7dcb304002dfced8c0fea289eb25f2da0 · fixed in c39087ad0b97fc11a3b058dfc8db9fd370762cb9; From c09440f7dcb304002dfced8c0fea289eb25f2da0 · fixed in f5089008f90c0a7c5520dff3934e0af00adf322d

  • Linux Linux

    4.6

  • KernelLinux

    From 4.6.0 · fixed in 5.10.265; From 5.11.0 · fixed in 5.15.216; From 5.16.0 · fixed in 6.1.178; From 6.2.0 · fixed in 6.6.145; From 6.7.0 · fixed in 6.12.97; From 6.13.0 · fixed in 6.18.40; From 6.19.0 · fixed in 7.1.5

References 8

git.kernel.org