A compiler optimization in GCC removes constant‑time masking by converting the code into conditional branches, breaking the side‑channel resistance of ECC scalar multiplication. This introduces a timing side‑channel that allows a local attacker who can observe execution time to reconstruct secret ECC keys. The weakness is classified as CWE‑203 and directly threatens the confidentiality of cryptographic material.

The vulnerability is present only in wolfSSL 5.8.4 when built for RISC‑V RV32I targets with the -O3 optimisation level. Builds for other architectures, earlier or later wolfSSL releases, and builds with different optimisation settings are not affected.

The CVSS score of 2.1 indicates low severity, and an EPSS score below 1 % shows a low likelihood of exploitation. The vulnerability is not listed in CISA’s KEV catalog. Attacks require local access and precise timing measurements, so practical exploitability is limited, yet the potential impact of compromised ECC keys could be catastrophic.