IPv6 Extension Header Checksum Bypass in Linux Kernel

Publication date: 2026-05-27

Last updated on: 2026-06-25

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: ipvs: skip ipv6 extension headers for csum checks Protocol checksum validation fails for IPv6 if there are extension headers before the protocol header. iph->len already contains its offset, so use it to fix the problem.

CVSS Scores

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Meta Information

Published

2026-05-27

Last Modified

2026-06-25

Generated

2026-07-07

AI Q&A

2026-05-27

EPSS Evaluated

2026-07-05

NVD

CVE-2026-45850

EUVD

EUVD-2026-32316

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	From 6.19 (inc) to 6.19.4 (exc)
linux	linux_kernel	From 5.16 (inc) to 6.1.176 (exc)
linux	linux_kernel	From 6.2 (inc) to 6.6.143 (exc)
linux	linux_kernel	From 5.11 (inc) to 5.15.210 (exc)
linux	linux_kernel	From 2.6.28 (inc) to 5.10.259 (exc)
linux	linux_kernel	From 6.13 (inc) to 6.18.36 (exc)
linux	linux_kernel	From 6.7 (inc) to 6.12.94 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability exists in the Linux kernel's IP Virtual Server (ipvs) component. It involves the protocol checksum validation process for IPv6 packets. Specifically, the validation fails if there are IPv6 extension headers present before the protocol header. The issue arises because the length field (iph->len) already includes the offset of these headers, but the checksum validation did not account for this, leading to incorrect validation. The fix involves using the length field properly to skip the IPv6 extension headers during checksum checks.

Impact Analysis

Because the protocol checksum validation can fail when IPv6 extension headers are present, this could allow malformed or malicious packets to bypass checksum verification. This might lead to incorrect processing of network packets, potentially causing network communication issues or enabling certain types of attacks that rely on evading checksum validation.

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