CVE-2026-59650

MTI/A0 DH agreement exponentiates unvalidated peer value

State: Published
Severity: 9.3 Critical
Published: Aug 3, 2026
Updated: Aug 3, 2026
Reserved: Jul 6, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	9.3 Critical	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber	bcorg

Weaknesses

CWE-20 Improper Input Validation

Affected Products

Product	Versions
BC-JAVALegion of the Bouncy Castle Inc.	before 1.85Affected
BC-LTS-JAVALegion of the Bouncy Castle Inc.	2.73.0 to before 2.73.12Affected

References

https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9059650vendor-advisory
https://github.com/bcgit/bc-java/commit/daeaae9d7075d04f40812e68671ebf4c777b5148patch

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