CVE-2026-12803

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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/bcgit/bc-java/commit/697794413ebf7bc5e3fce609a707826ba52981af	Patch
https://github.com/bcgit/bc-java/commit/7d79aa76e984da85f2a541cae8ba2ae56e1713bc	Patch
https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9012803	Third Party Advisory Patch

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:bouncycastle:bc-java::::::::
	cpe:2.3:a:bouncycastle:bouncy_castle_for_java_lts::::::::

History

No history.

Information

Published : 2026-08-03 04:16

Updated : 2026-09-02 14:37

NVD link : CVE-2026-12803

Mitre link : CVE-2026-12803

CVE.ORG link : CVE-2026-12803

JSON object : View

Products Affected

bouncycastle

bouncy_castle_for_java_lts
bc-java

CWE

CWE-354

Improper Validation of Integrity Check Value

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