REDHAT-BUG-2510260: High severity Bouncy Castle Bouncy Castle for Java vulnerability

Q: Which deployments require an update?

Bouncy Castle for Java releases before 1.85 are affected. Bouncy Castle for Java LTS releases before 2.73.12 are also affected.

Q: Under what condition is the MAC binding failure relevant?

The issue occurs when KCCMBlockCipher is used without associated authenticated data (AAD). In that condition, the MAC does not bind the nonce, enabling cross-nonce AEAD forgery.

Published Aug 3, 2026

Updated

In Bouncy Castle for Java before 1.85, KCCMBlockCipher MAC does not bind nonce when AAD is absent (cross-nonce AEAD forgery). This issue also affects Bouncy Castle for Java LTS before 2.73.12.

Affected Software

2 affected components

Bouncy Castle Bouncy Castle for Java<1.85

Bouncy Castle Bouncy Castle for Java LTS<2.73.12

Event History

Aug 3, 2026

Data Sourced

via Red Hat·04:01 AM

DescriptionSeverityAffected Software

Frequently Asked Questions

Which deployments require an update?

Bouncy Castle for Java releases before 1.85 are affected. Bouncy Castle for Java LTS releases before 2.73.12 are also affected.

Under what condition is the MAC binding failure relevant?

The issue occurs when KCCMBlockCipher is used without associated authenticated data (AAD). In that condition, the MAC does not bind the nonce, enabling cross-nonce AEAD forgery.

REDHAT-BUG-2510260: High severity Bouncy Castle Bouncy Castle for Java vulnerability

Affected Software

Event History

Frequently Asked Questions

Which deployments require an update?

Under what condition is the MAC binding failure relevant?

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Frequently Asked Questions

Which deployments require an update?

Under what condition is the MAC binding failure relevant?