CVE-2026-59650
Received Received - Intake

Bouncy Castle Java DH Key Agreement Validation Flaw

Publication date: 2026-08-03

Last updated on: 2026-08-03

Assigner: bcorg

Description
In Bouncy Castle for Java before 1.85, MTI/A0 DH agreement exponentiates unvalidated peer value. This issue also affects Bouncy Castle for Java LTS before 2.73.12.

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Meta Information

Published
2026-08-03
Last Modified
2026-08-03
Generated
2026-08-03
AI Q&A
2026-08-03
EPSS Evaluated
N/A
NVD
CVE-2026-59650
EUVD
EUVD-2026-52024

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
bouncy_castle bcprov_jdk15on to 1.85 (exc)
bouncy_castle bcprov_jdk15on to 2.73.12 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-20 The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

Attack-Flow Graph

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Executive Summary

This vulnerability in Bouncy Castle for Java before version 1.85 involves the MTI/A0 Diffie-Hellman (DH) agreement process. It allows an attacker to exponentiate an unvalidated peer value, which could lead to security issues during key exchange.

Detection Guidance

This vulnerability involves unvalidated peer values in DH agreement in Bouncy Castle for Java. Detection requires checking the Bouncy Castle library version in use. Commands like 'find / -name "bcprov*.jar" -exec jar tf {} \; 2>/dev/null | grep -i 'Version' 2>/dev/null' can help identify the version. Compare the detected version against 1.85 (or LTS 2.73.12) to determine exposure.

Impact Analysis

An attacker could exploit this to perform man-in-the-middle attacks or decrypt sensitive communications. Systems using vulnerable versions of Bouncy Castle may be exposed to unauthorized access or data breaches.

Compliance Impact

This vulnerability could lead to unauthorized data access or exposure, violating confidentiality requirements in GDPR and HIPAA. Organizations using affected versions may fail compliance audits due to inadequate security controls.

Mitigation Strategies

Update Bouncy Castle for Java to version 1.85 or later. If using LTS, upgrade to version 2.73.12 or later. Remove or disable affected versions if immediate update is not possible.

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