The vulnerability in Bouncy Castle for Java before version 1.85 and certain LTS and FIPS versions involves the PKCS#8 / PBES2 decryptors honoring an unbounded key derivation function (KDF) cost parameter supplied by input. This lack of limits on the KDF cost can cause excessive resource consumption during decryption operations, potentially leading to denial of service. The affected versions include Bouncy Castle for Java before 1.85, LTS before 2.73.12, and FIPS versions before bcpkix-fips 1.0.12 (1.0.X series), 2.0.12 (2.0.X series), and 2.1.12 (2.1.X series). There are no known exploits in the wild, and no patch information is provided in the source data.

The vulnerability allows an attacker to specify an unbounded KDF cost parameter during PKCS#8 / PBES2 decryption, which can cause excessive CPU and memory consumption. This can result in denial of service conditions by exhausting system resources. There is no indication of confidentiality, integrity, or availability compromise beyond resource exhaustion. No known active exploitation has been reported.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no patch or official fix information is provided, users should monitor vendor communications for updates. Until a fix is available, consider limiting exposure to untrusted inputs that trigger PKCS#8 / PBES2 decryption or applying resource usage limits at the application or system level to mitigate potential denial of service.