CVE-2026-72407
Received Received - Intake

Buffer Overflow in Linux Kernel Geneve GRO Completion

Vulnerability report for CVE-2026-72407, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-15

Last updated on: 2026-08-15

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: geneve: validate inner network offset in geneve_gro_complete() Even with both paths gated on gs->gro_hint, geneve_gro_complete() re-derives the inner dispatch type and length from the packet and the current gs->gro_hint, independently of geneve_gro_receive(). The two can disagree if gs->gro_hint flips under a concurrent geneve_quiesce()/ geneve_unquiesce() (sk_user_data is NULL across a synchronize_net()), or if the re-read option bytes differ from the ones receive parsed. geneve_gro_receive() already records the inner network header position in NAPI_GRO_CB()->inner_network_offset. Have geneve_gro_complete() compute the offset it is about to dispatch at, adding ETH_HLEN in the ETH_P_TEB case where eth_gro_complete() steps over the inner MAC header, and bail out if it lands past inner_network_offset. Use a lower bound rather than exact equality: between gh_len and the inner L3 header, geneve_gro_receive() may also have pulled an inner VLAN tag (vlan_gro_receive() advances the recorded offset past it), which only moves inner_network_offset further out. A valid frame therefore always satisfies inner_nh <= inner_network_offset, while a gh_len inflated by a hint gro_receive() did not honour dispatches past the validated inner header, i.e. the out-of-bounds completion. Only the latter is rejected.

CVSS Scores

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Meta Information

Published
2026-08-15
Last Modified
2026-08-15
Generated
2026-08-15
AI Q&A
2026-08-15
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Currently, no data is known.

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a Linux kernel vulnerability in the GENEVE (Generic Network Virtualization Encapsulation) protocol implementation. It involves a race condition in the GRO (Generic Receive Offload) processing where the inner network header offset can be miscalculated. This happens when the gro_hint changes concurrently or when re-read packet bytes differ from the parsed values. The vulnerability could lead to out-of-bounds memory access during packet processing.

Impact Analysis

This vulnerability may allow an attacker to cause a denial of service (DoS) by crashing the system or corrupting memory. It could also potentially enable unauthorized access or data leaks if exploited to manipulate network packet processing. Systems using GENEVE tunnels with GRO enabled are most at risk.

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