llc: reserve device headroom for allocated frames

Summary

In the Linux kernel, the following vulnerability has been resolved: llc: reserve device headroom for allocated frames llc_alloc_frame() reserves link-layer headroom using the device type. This is insufficient for stacked Ethernet devices such as VLAN devices, where vlan_dev_hard_header() pushes a VLAN header before the lower device's Ethernet header. An LLC response on such a device can therefore underflow skb headroom in eth_header(). Use LL_RESERVED_SPACE() to account for the device's actual required headroom while preserving the existing LLC device-type check.

Timeline

1. Oct 18, 2026, 3:17 PM UTCCVE published
2. Oct 19, 2026, 9:21 AM UTCRecord last updated

Affected versions

• Linux Linux

  From bf9ae5386bca8836c16e69ab8fdbe46767d7452a · fixed in 018020f5a48cc86fdd6dc2d380f6c70443ae7639; From bf9ae5386bca8836c16e69ab8fdbe46767d7452a · fixed in 3a3f57c4061d9e9cc3bc04205d36ce41ae3406c1; From bf9ae5386bca8836c16e69ab8fdbe46767d7452a · fixed in 7c38524b2b2456bd33cb360420da6cbf9cad1b33; From bf9ae5386bca8836c16e69ab8fdbe46767d7452a · fixed in 1937222c2511ac91377d39f28106c34734f5f8c6; From bf9ae5386bca8836c16e69ab8fdbe46767d7452a · fixed in 16ceac2daa89dd16917bc488ab05b9dd6961a603; From bf9ae5386bca8836c16e69ab8fdbe46767d7452a · fixed in e06f8b6e27cc616d3c587e9784c4a033eb310a16; From bf9ae5386bca8836c16e69ab8fdbe46767d7452a · fixed in 3361c93e417384ebf28003e0fb6d5304653d3b05; From bf9ae5386bca8836c16e69ab8fdbe46767d7452a · fixed in 72b5b9a28b996e09b8b5b944370c79851bb68f52

• Linux Linux

  2.6.34

• KernelLinux

  From 2.6.34 · fixed in 5.10.271; From 5.11.0 · fixed in 5.15.222; From 5.16.0 · fixed in 6.1.189; From 6.2.0 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.112; From 6.13.0 · fixed in 6.18.55; From 6.19.0 · fixed in 7.2.9

References 8