CVE-2026-72351
Received Received - Intake

GUE Private Option Length Validation in Linux Kernel

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: gue: validate REMCSUM private option length GUE private flags can indicate that remote checksum offload metadata is present. The private flags field itself is accounted for by guehdr_flags_len(), but guehdr_priv_flags_len() currently returns 0 even when GUE_PFLAG_REMCSUM is set. This lets a packet with only the private flags field pass validate_gue_flags(), after which gue_remcsum() and gue_gro_remcsum() read the missing REMCSUM start/offset fields from the following bytes. Account for GUE_PLEN_REMCSUM when GUE_PFLAG_REMCSUM is present so that malformed packets are rejected during option validation.

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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
CVE-2026-72351
EUVD
EUVD-2026-59250

Affected Vendors & Products

Currently, no data is known.

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Exploitability

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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves incorrect validation of the GUE (Generic UDP Encapsulation) private option length. When the REMCSUM private flag is set, the system fails to account for the required length of the REMCSUM metadata fields. This allows malformed packets to bypass validation checks, potentially leading to incorrect processing of network packets.

Detection Guidance

This vulnerability involves improper validation of GUE private flags in the Linux kernel, specifically related to REMCSUM metadata. Detection requires inspecting network packets for malformed GUE headers with GUE_PFLAG_REMCSUM set but missing REMCSUM start/offset fields. Use packet capture tools like tcpdump or Wireshark to analyze GUE-encapsulated traffic for invalid private flag lengths.

Impact Analysis

This vulnerability could allow attackers to send specially crafted network packets that bypass security checks. This might lead to unauthorized access, data leaks, or denial-of-service conditions on affected systems running vulnerable Linux kernel versions.

Mitigation Strategies

Apply the latest Linux kernel security patches to address the improper validation of GUE private flags. Monitor vendor advisories for updates to affected distributions. If immediate patching is not possible, consider disabling GUE offloading features or filtering malformed packets at the network perimeter until the fix is applied.

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