The vulnerability arises from a lack of a constant‑time implementation for the __muldi3 subroutine on RISC‑V RV32I, causing the compiler‑injected 64‑bit multiplication to take variable time depending on the operands. This creates a timing side‑channel that can expose private keys or other sensitive data processed by wolfSSL’s SP math functions such as sp_256_mul_9 and sp_256_sqr_9. The weakness is classified as CWE‑203.

wolfSSL version 5.8.4 running on RISC‑V RV32I architecture. The issue manifests in all instances that use the affected SP math functions in the library; no other vendors or products are listed.

CVSS is 2.1 and EPSS is below 1 %, with no KEV listing, indicating modest base severity. However, an attacker who can repeatedly invoke the multiplication routine and measure timing can potentially recover secret data. The likely attack vector is timing analysis of the multiply routine; this is inferred from the description that execution time varies with operand values. Because the problem depends on observable timing differences, the risk is not negligible for systems performing sensitive crypto operations.