Critical severity · published Aug 15, 2026
CVE-2026-72408
geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint
10.0
CVSS
0.6%
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved:
geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint
geneve_gro_receive() reads the GRO hint through geneve_sk_gro_hint_off(),
which honours it only when the socket enabled IFLA_GENEVE_GRO_HINT
(gs->gro_hint). geneve_gro_complete() instead calls the low-level
geneve_opt_gro_hint_off() and acts on the hint unconditionally.
On a tunnel without the hint, receive aggregates the frames as plain
ETH_P_TEB while complete still honours an attacker-supplied hint option: it
inflates gh_len by gro_hint->nested_hdr_len (u8) and redirects the dispatch
type, so the inner gro_complete handler runs at nhoff + gh_len, an offset
receive never pulled nor validated, reading out of bounds of the skb head:
BUG: KASAN: slab-out-of-bounds in ipv6_gro_complete (net/ipv6/ip6_offload.c:196)
Read of size 1 at addr ffff88800fe91980 by task exploit/153
ipv6_gro_complete (net/ipv6/ip6_offload.c:196)
geneve_gro_complete (drivers/net/geneve.c:965)
udp_gro_complete (net/ipv4/udp_offload.c:940)
inet_gro_complete (net/ipv4/af_inet.c:1621)
__gro_flush (net/core/gro.c:306)
Gate the complete path on gs->gro_hint too via geneve_sk_gro_hint_off(), so
both paths agree. Tunnels that enable the hint are unaffected.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 46% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux · Linux
fd0dd796576e1a560e1441e665810129f0a82be0 before 49c2e7c0a69999a75ef5eaebe1559a20d0b3c15a; fd0dd796576e1a560e1441e665810129f0a82be0 before 2651c174445884ac9e85622aeade9c1f7b98d8e5; 7.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-72408
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-72408
git.kernel.org
https://git.kernel.org/stable/c/2651c174445884ac9e85622aeade9c1f7b98d8e5
git.kernel.org
https://git.kernel.org/stable/c/49c2e7c0a69999a75ef5eaebe1559a20d0b3c15a
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