An integer underflow in the packet sniffer’s ChaCha decrypt path misinterprets a TLS record length, causing the AEAD routine to read a large, invalid buffer. This out‑of‑bounds read terminates the process, yielding a denial‑of‑service condition. The flaw is a classic integer underflow (CWE‑191) that does not disclose data or alter the encrypted content.

wolfSSL library versions 5.9.0 and earlier contain the vulnerable logic. Any deployment that activates the packet sniffer on traffic that includes TLS records, regardless of the host operating system or programming language, may be affected.

With a CVSS score of 2.1 the vulnerability is considered low severity. The exploit does not require authentication and can be triggered remotely by sending malformed TLS Application Data records. The attacker only gains a process crash, leading to denial of service. There is no evidence of active exploitation, as it is not listed in the CISA known exploited vulnerabilities catalog, and the EPSS score is unavailable.