The vulnerability in Bouncy Castle for Java allows an attacker to trigger excessive resource consumption by exploiting the PKCS#12 MAC and bag‑decryption key‑derivation‑function iteration‑count bound. By supplying a PKCS#12 file with an iteration count set to a very low or otherwise unchecked value, the library will perform an unintended amount of cryptographic work, potentially exhausting CPU or memory and causing the application to become unresponsive. The weakness is classified as CWE‑770, indicating resource exhaustion.

Affected are the Bouncy Castle products from the Legion of the Bouncy Castle Inc.: BC-JAVA and BC-LTS-JAVA before version 1.85 and 2.73.12 respectively, and the FIPS-enabled BC-FJA before bc‑fips 1.0.2.7 (1.0.X series), 2.0.2 (2.0.X series), and 2.1.3 (2.1.X series). These libraries are used in Java applications that process PKCS#12 keystores and certificates.

The CVSS score of 5.3 indicates moderate severity, and the exploit probability is unknown because the EPSS score is not available. The vulnerability is not listed in the CISA KEV catalog. Likely attack vectors involve sending crafted PKCS#12 files to any service or application that loads them using Bouncy Castle; this can be performed remotely if the service accepts user‑supplied files. Exploitation would cause denial of service by inducing excessive crypto work, with the impact limited to the affected process and system resources.