{"id":"CVE-2026-72408","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-72408","summary":"geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ngeneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint\n\ngeneve_gro_receive() reads the GRO hint through geneve_sk_gro_hint_off(),\nwhich honours it only when the socket enabled IFLA_GENEVE_GRO_HINT\n(gs->gro_hint). geneve_gro_complete() instead calls the low-level\ngeneve_opt_gro_hint_off() and acts on the hint unconditionally.\n\nOn a tunnel without the hint, receive aggregates the frames as plain\nETH_P_TEB while complete still honours an attacker-supplied hint option: it\ninflates gh_len by gro_hint->nested_hdr_len (u8) and redirects the dispatch\ntype, so the inner gro_complete handler runs at nhoff + gh_len, an offset\nreceive never pulled nor validated, reading out of bounds of the skb head:\n\n  BUG: KASAN: slab-out-of-bounds in ipv6_gro_complete (net/ipv6/ip6_offload.c:196)\n  Read of size 1 at addr ffff88800fe91980 by task exploit/153\n   ipv6_gro_complete (net/ipv6/ip6_offload.c:196)\n   geneve_gro_complete (drivers/net/geneve.c:965)\n   udp_gro_complete (net/ipv4/udp_offload.c:940)\n   inet_gro_complete (net/ipv4/af_inet.c:1621)\n   __gro_flush (net/core/gro.c:306)\n\nGate the complete path on gs->gro_hint too via geneve_sk_gro_hint_off(), so\nboth paths agree. Tunnels that enable the hint are unaffected.","published":"2026-08-15T05:56:31.477Z","modified":"2026-08-18T03:56:55.785648408Z","cvss":{"score":10,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"7.1.5"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2651c174445884ac9e85622aeade9c1f7b98d8e5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/49c2e7c0a69999a75ef5eaebe1559a20d0b3c15a"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72408.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72408"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-18T03:56:55.785648408Z"}}