Covert timing channel vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA core modules arises from covert timing vulnerabilities within FrodoEngine.Java files, allowing extraction of private key material by measuring execution timings, thereby breaking confidentiality of encrypted communications. The flaw, categorized as CWE‑385, is confined to the core implementation of the FrodoKEM key‑encapsulation mechanism.

The vulnerability impacts all BC‑JAVA core modules from version 1.71 up to, but not including, version 1.84. Users running these earlier releases are susceptible.

The CVSS score of 8.9 denotes a high severity weakness. The EPSS score of less than 1% indicates a low probability of exploitation at the time of this analysis, and the issue is not listed in the CISA KEV catalog. The nature of the flaw suggests that an attacker who can conduct precise timing measurements of cryptographic operations in FrodoEngine.Java could recover private keys. The likely attack vector is a side‑channel attack that requires the attacker to trigger or observe FrodoEngine.Java operations, which may be feasible in environments where the application is exposed to an active network or on shared hosting platforms that permit timing analysis.