Improper Input Validation Affecting org.bouncycastle:bcprov-jdk18on package, versions [,1.85)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-JAVA-ORGBOUNCYCASTLE-18512810
- published4 Aug 2026
- disclosed3 Aug 2026
- creditUnknown
Introduced: 3 Aug 2026
NewCVE-2026-59650 (opens in a new tab)How to fix?
Upgrade org.bouncycastle:bcprov-jdk18on to version 1.85 or higher.
Overview
Affected versions of this package are vulnerable to Improper Input Validation in the calculateAgreement(pub, message) method of the DHAgreement class, which raises the peer-supplied message to the power of the local static private key x without any range or subgroup-membership check, while only the pub parameter is validated through DHPublicKeyParameters. A malicious peer can recover the full static private key by repeatedly sending small-order elements (0, 1, p-1, or elements of small subgroups) as message, since each exchange leaks the key modulo a small prime and the values combine via the Chinese Remainder Theorem. This affects only the MTI/A0 two-pass DHAgreement variant and not DHBasicAgreement, and it requires the application to reuse a static Diffie-Hellman private key across exchanges.