CVE-2026-43384

Analyzed Analyzed - Analysis Complete

Constant-Time MAC Comparison Fix in Linux Kernel TCP-AO

Publication date: 2026-05-08

Last updated on: 2026-05-26

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: net/tcp-ao: Fix MAC comparison to be constant-time To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this.

CVSS Scores

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Meta Information

Published

2026-05-08

Last Modified

2026-05-26

Generated

2026-07-09

AI Q&A

2026-05-08

EPSS Evaluated

2026-07-08

NVD

CVE-2026-43384

EUVD

EUVD-2026-28690

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	From 6.13 (inc) to 6.18.19 (exc)
linux	linux_kernel	From 6.7 (inc) to 6.12.78 (exc)
linux	linux_kernel	From 6.19 (inc) to 6.19.9 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel relates to the way Message Authentication Codes (MACs) are compared in the net/tcp-ao component.

The issue was that MAC comparisons were not done in constant time, which could allow timing attacks.

The fix involved using an appropriate helper function to ensure MAC comparisons are performed in constant time, preventing attackers from gaining information based on the time it takes to compare MACs.

Impact Analysis

If exploited, this vulnerability could allow an attacker to perform timing attacks to potentially deduce the MAC values used in TCP authentication.

This could lead to unauthorized access or manipulation of network communications that rely on these MACs for integrity and authentication.

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