Inadequate Encryption Strength Affecting org.bouncycastle:bcprov-jdk15to18 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.
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- published4 Aug 2026
- disclosed3 Aug 2026
- creditUnknown
Introduced: 3 Aug 2026
NewCVE-2026-59651 (opens in a new tab)How to fix?
Upgrade org.bouncycastle:bcprov-jdk15to18 to version 1.85 or higher.
Overview
org.bouncycastle:bcprov-jdk15to18 is a Java implementation of cryptographic algorithms.
Affected versions of this package are vulnerable to Inadequate Encryption Strength in the BcKeyStoreSpi.engineLoad() method, which for legacy BKS keystore versions 0 and 1 passes hMac.getMacSize() (20 bytes for SHA-1) to generateDerivedMacParameters(), where PKCS12ParametersGenerator divides it by 8 and yields a 16-bit MAC key. An attacker with access to a .bks file can brute-force the 2^16 possible keys offline and produce a valid MAC over a modified store, for example injecting a rogue trusted CA, by setting the file's version integer to a legacy value that reaches the weak-key branch. This requires the attacker to supply or modify a .bks keystore that the application loads, and the org.bouncycastle.bks.enable_v1 property does not gate this path because the default BKS type reaches the weak derivation in engineLoad() regardless.