CVE-2026-58063: BCFKS keystore load honours unbounded KDF cost from untrusted file

Affects Bouncy Castle for Java FIPS (BC-FJA) bc-fips-debug before 1.0.2.7 (1.0.X series), 2.0.2 (2.0.X series) and 2.1.3 (2.1.X series). BcFKSKeyStoreSpi.engineLoad() takes the KDF algorithm and parameters from the untrusted keystore before running verifyMac(), then feeds the file-supplied PBKDF2 iteration count or scrypt cost directly into derivation with no ceiling. A modified .bcfks file declaring an iteration count near 2^31, or scrypt parameters sized to available RAM, consumes minutes to hours of CPU or gigabytes of memory before the MAC mismatch is detected.