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CVE-2026-74667

net/packet: reset the MAC header on the packet-socket transmit path

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.265, 5.15.216, 6.1.183, 6.6.152, 6.12.104, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

In the Linux kernel, the following vulnerability has been resolved: net/packet: reset the MAC header on the packet-socket transmit path packet_parse_headers() resets the MAC header only for a SOCK_RAW frame whose socket did not bind a protocol. A protocol-bound SOCK_RAW socket, any SOCK_DGRAM frame, and the legacy SOCK_PACKET path therefore leave skb->mac_header unset here. For frames sent via __dev_queue_xmit() this is harmless: it resets the MAC header unconditionally. But the packet-socket PACKET_QDISC_BYPASS path uses dev_direct_xmit(), which does not, so the frame reaches ndo_start_xmit() with the MAC header unset. A driver that reads eth_hdr(skb) on transmit then dereferences skb->head + (u16)~0, an out-of-bounds access ~64 KiB past the head -- the same class fixed for one consumer in commit f5089008f90c ("macsec: do not read an unset MAC header in macsec_encrypt()"). packet_parse_headers() runs only on the transmit path, where skb->data points at the start of the L2 header for every packet-socket type regardless of its length: SOCK_RAW and SOCK_PACKET carry a user-supplied header and SOCK_DGRAM has one built by dev_hard_header(). Reset the MAC header unconditionally, mirroring __dev_queue_xmit(), so the frame is anchored on the bypass path too. Found by 0sec (https://0sec.ai) using automated source analysis; verified against source and matched to the macsec KASAN report in f5089008f90c. Compile-tested.

Timeline

  1. CVE published
  2. CISA SSVC assessment

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

  3. Record last updated

Affected versions

  • Linux Linux

    From 75c65772c3d18447d62d3aca5f91b06c16cc25e4 · fixed in 1e43a1d66615f411d427f9df1f46dd049d9e3681; From 75c65772c3d18447d62d3aca5f91b06c16cc25e4 · fixed in 4057853a91fb796c4f47c7d1baf1aa085394148e; From 75c65772c3d18447d62d3aca5f91b06c16cc25e4 · fixed in 2610ed4e86a4590234a9d70518c469751c5af231; From 75c65772c3d18447d62d3aca5f91b06c16cc25e4 · fixed in b47ba8fe6e1d2df8c92048de5afafd059447dc30; From 75c65772c3d18447d62d3aca5f91b06c16cc25e4 · fixed in 284f3e7a3f1a743fdf89e304fd1f19d5ffcff46d; From 75c65772c3d18447d62d3aca5f91b06c16cc25e4 · fixed in 971aa7d99242bbf09513e27b7a243f0b29ff23ae; From 75c65772c3d18447d62d3aca5f91b06c16cc25e4 · fixed in fdd4d7d52358a58e351dd9d82530c04eba8ccd7a; From 75c65772c3d18447d62d3aca5f91b06c16cc25e4 · fixed in c2707480cfbf19c7619acc9c089d17f20869821f

  • Linux Linux

    5.1

  • KernelLinux

    From 5.1.0 · fixed in 5.10.265; From 5.11.0 · fixed in 5.15.216; From 5.16.0 · fixed in 6.1.183; From 6.2.0 · fixed in 6.6.152; From 6.7.0 · fixed in 6.12.104; From 6.13.0 · fixed in 6.18.45; From 6.19.0 · fixed in 7.1.9

References 8

git.kernel.org