CVE-2026-72408

In the Linux kernel, the following vulnerability has been resolved:

geneve: gate GRO hint in genevegrocomplete() on gs->gro_hint

genevegroreceive() reads the GRO hint through geneveskgrohintoff(),

which honours it only when the socket enabled IFLAGENEVEGRO_HINT

(gs->grohint). genevegro_complete() instead calls the low-level

geneveoptgrohintoff() and acts on the hint unconditionally.

On a tunnel without the hint, receive aggregates the frames as plain

ETHPTEB while complete still honours an attacker-supplied hint option: it

inflates ghlen by grohint->nestedhdrlen (u8) and redirects the dispatch

type, so the inner grocomplete handler runs at nhoff + ghlen, an offset

receive never pulled nor validated, reading out of bounds of the skb head:

  BUG: KASAN: slab-out-of-bounds in ipv6grocomplete (net/ipv6/ip6_offload.c:196)

  Read of size 1 at addr ffff88800fe91980 by task exploit/153

   ipv6grocomplete (net/ipv6/ip6_offload.c:196)

   genevegrocomplete (drivers/net/geneve.c:965)

   udpgrocomplete (net/ipv4/udp_offload.c:940)

   inetgrocomplete (net/ipv4/af_inet.c:1621)

   _groflush (net/core/gro.c:306)

Gate the complete path on gs->grohint too via geneveskgrohint_off(), so

both paths agree. Tunnels that enable the hint are unaffected.