RSA PKCS#1 Verification Vulnerability in Bouncy Castle for Java
CVE-2026-12860

8.7HIGH

Key Information:

Vendor

Legion Of The Bouncy Castle Inc.

Status
Bc-java
Bc-lts-java
Vendor
CVE Published:
3 August 2026

What is CVE-2026-12860?

A security vulnerability has been identified in Bouncy Castle for Java affecting the RSA PKCS#1 verification process. Specifically, prior to version 1.85 and in the LTS version before 2.73.12, the verification mechanism erroneously skips the last two hash bytes when processing NULL-omitted paths. This oversight could lead to improper verification outcomes, posing a risk to applications relying on this cryptographic library.

Affected Version(s)

BC-JAVA all 0 < 1.85

BC-LTS-JAVA all 2.73.0 < 2.73.12

References

https://github.com/bcgit/bc-java/wiki/CVE-2026-12860
vendor-advisory
https://github.com/bcgit/bc-java/commit/ea5970ea9b2fb91d7...
patch

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Alex Gaynor in collaboration with Claude and Anthropic Research
.