CVE-2026-12803: KCCMBlockCipher MAC does not bind nonce when AAD is absent (cross-nonce AEAD forgery)
High · CVSS 7.5 (CVSS 3.1)EPSS 0.24%, 15th percentilePublished Updated Assigner: bcorg
Description
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.
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N · CWE-354
Tracked companies
Mapped from the CVE’s affected-product data, NVD CPE matches, vendor advisories or package feeds. A mapping means the vendor’s software is named, not that its hosted service was exposed.
Status incidents that name it
No tracked status incident names this CVE.
Affected vendors and products
Legion of the Bouncy Castle Inc.: BC-JAVALegion of the Bouncy Castle Inc.: BC-LTS-JAVA
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- github.com/bcgit/bc-java/commit/697794413ebf7bc5e3fce609a707826ba52981af (opens in new tab)
- github.com/bcgit/bc-java/commit/7d79aa76e984da85f2a541cae8ba2ae56e1713bc (opens in new tab)
- github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9012803 (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)