CVE-2026-43383
Analyzed Analyzed - Analysis Complete
TCP MD5 Signature Verification Timing Attack Fix in Linux Kernel

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-md5: 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.
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Meta Information
Published
2026-05-08
Last Modified
2026-05-26
Generated
2026-06-19
AI Q&A
2026-05-08
EPSS Evaluated
2026-06-18
NVD
CVE-2026-43383
EUVD
EUVD-2026-28689
Affected Vendors & Products
Showing 8 associated CPEs
Vendor Product Version / Range
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel From 6.2 (inc) to 6.6.130 (exc)
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)
linux linux_kernel From 5.11 (inc) to 6.1.167 (exc)
linux linux_kernel From 2.6.20 (inc) to 5.10.253 (exc)
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Exploitability
CWE
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability is related to the Linux kernel's TCP MD5 implementation. Specifically, the issue was that the Message Authentication Codes (MACs) were not being compared in constant time, which could allow timing attacks. The fix involved using an appropriate helper function to ensure that MAC comparisons are done in constant time, preventing attackers from gaining information based on the time it takes to compare MACs.

Impact Analysis

If the MAC comparison is not done in constant time, an attacker could potentially exploit timing differences to perform a timing attack. This could allow the attacker to deduce the MAC value, compromising the integrity and authenticity of TCP connections that rely on MD5 for security.

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