Linux Kernel up to 7.1.4 geneve drivers/net/geneve.c geneve_gro_complete gro_hint out-of-bounds

Summaryinfo

A vulnerability categorized as very critical has been discovered in Linux Kernel up to 7.1.4. This affects the function geneve_gro_complete of the file drivers/net/geneve.c of the component geneve. The manipulation of the argument gro_hint results in out-of-bounds. This vulnerability is cataloged as CVE-2026-72408. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability classified as very critical has been found in Linux Kernel up to 7.1.4. Affected is the function geneve_gro_complete of the file drivers/net/geneve.c of the component geneve. The manipulation of the argument gro_hint with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-72408 since 08/09/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 08/15/2026).

Upgrading to version 7.1.5 or 7.2-rc1 eliminates this vulnerability. Applying the patch 49c2e7c0a69999a75ef5eaebe1559a20d0b3c15a/2651c174445884ac9e85622aeade9c1f7b98d8e5 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

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