CVE-2026-3579 in wolfSSL
Summary
by MITRE • 03/19/2026
wolfSSL 5.8.4 on RISC-V RV32I architectures lacks a constant-time software implementation for 64-bit multiplication. The compiler-inserted __muldi3 subroutine executes in variable time based on operand values. This affects multiple SP math functions (sp_256_mul_9, sp_256_sqr_9, etc.), leading to a timing side-channel that may expose sensitive cryptographic data.
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Analysis
by VulDB Data Team • 03/24/2026
The vulnerability identified as CVE-2026-3579 represents a critical timing side-channel weakness in wolfSSL version 5.8.4 when deployed on RISC-V RV32I architectures. This issue stems from the absence of constant-time software implementations for 64-bit multiplication operations within the cryptographic library. The root cause lies in the compiler-inserted __muldi3 subroutine which executes in variable time depending on the input operand values rather than maintaining consistent execution duration regardless of the data processed. This fundamental flaw directly impacts the security of cryptographic operations that rely on software-based mathematical functions, particularly those used in elliptic curve cryptography and other public key algorithms. The vulnerability specifically affects multiple SP math functions including sp_256_mul_9 and sp_256_sqr_9, which are essential components in cryptographic computations involving 256-bit integers.
The operational impact of this vulnerability extends beyond simple performance degradation to represent a serious threat to cryptographic security. Attackers can exploit the timing variations in multiplication operations to infer information about secret keys or other sensitive cryptographic data through side-channel analysis techniques. This weakness creates opportunities for timing attacks that can potentially reconstruct private keys or decrypt sensitive communications. The vulnerability is particularly concerning in embedded systems and IoT devices that utilize RISC-V RV32I processors, where such systems often handle critical cryptographic operations without adequate protection against timing-based information leakage. The variable-time execution characteristics of the multiplication subroutine enable adversaries to perform statistical analysis on timing measurements to deduce cryptographic secrets, fundamentally compromising the security guarantees that cryptographic algorithms are designed to provide.
Security practitioners should recognize this vulnerability as a direct violation of the constant-time execution principles that are fundamental to secure cryptographic implementation. The issue aligns with CWE-376, which addresses improper handling of timing information in cryptographic operations, and relates to ATT&CK technique T1059.001 for potential exploitation through software-based side-channel attacks. Mitigation strategies must include implementing constant-time multiplication algorithms specifically designed for the target architecture, ensuring that all mathematical operations maintain consistent execution time regardless of input values. Organizations should prioritize updating to wolfSSL versions that include proper constant-time implementations or implement custom fixes that replace the problematic compiler-inserted multiplication routines with secure alternatives. Additionally, system architects should consider architectural mitigations such as adding noise injection or other countermeasures to prevent timing analysis attacks. The vulnerability underscores the importance of thorough security testing on target architectures, particularly when dealing with embedded systems where compiler optimizations may introduce unexpected security weaknesses that are not apparent in traditional x86 or ARM environments.