Full Report
A critical vulnerability in the wolfSSL SSL/TLS library can weaken security via improper verification of the hash algorithm or its size when checking Elliptic Curve Digital Signature Algorithm (ECDSA) signatures. [...]
Analysis Summary
# Vulnerability: wolfSSL Improper Verification of Cryptographic Signatures
## CVE Details
- **CVE ID:** CVE-2026-5194
- **CVSS Score:** 9.8 (Critical) - *Note: Based on Red Hat's maximum severity rating mentioned in the text.*
- **CWE:** CWE-347: Improper Verification of Cryptographic Signature
## Affected Systems
- **Products:** wolfSSL (lightweight SSL/TLS library)
- **Versions:** All versions prior to v5.9.1.
- **Configurations:** Systems utilizing ECDSA/ECC, DSA, ML-DSA, Ed25519, or Ed448 signature algorithms. High risk for builds where both ECC and EdDSA or ML-DSA are active.
## Vulnerability Description
The vulnerability stems from a failure in the cryptographic validation routine to properly check the hash algorithm, Object Identifier (OID), and digest size when verifying digital signatures. Specifically, the library allows digests that are smaller than permitted or smaller than appropriate for the specific key type. Because the system fails to enforce minimum digest requirements, it may accept signatures that are cryptographically weak or mathematically flawed, effectively weakening the security of the authentication process.
## Exploitation
- **Status:** Vulnerability documented; PoC not explicitly stated as public in the text, but the flaw is verified by security researchers.
- **Complexity:** Medium (Requires creating a forged certificate with a reduced digest size).
- **Attack Vector:** Network (Remote attackers can present forged certificates to vulnerable clients/servers).
## Impact
- **Confidentiality:** High (Potential for Man-in-the-Middle attacks to intercept encrypted traffic).
- **Integrity:** High (Attacker can forge digital identities, allowing for the acceptance of malicious files, servers, or connections).
- **Availability:** Low (Primary impact is on authentication and trust rather than system uptime).
## Remediation
### Patches
- **wolfSSL v5.9.1:** Users should upgrade immediately to version 5.9.1 or later.
### Workarounds
- No specific software workarounds are offered; however, administrators should monitor for downstream security advisories from vendors who bundle wolfSSL (e.g., Linux distributions, IoT firmware, and SDKs).
## Detection
- **Indicators of Compromise:** Presence of certificates using unusually small digest sizes for ECDSA or ML-DSA signatures.
- **Detection Methods and Tools:**
- Audit library versions on embedded systems and containers.
- Monitor TLS handshakes for non-standard or weak cryptographic parameters.
- Check for downstream advisories from vendors like Red Hat (note that Red Hat confirmed MariaDB is *not* affected as it uses OpenSSL).
## References
- **Vendor Advisory:** hxxps[://]github[.]com/advisories/GHSA-f5h9-5q52-qrx7
- **Release Notes:** hxxps[://]github[.]com/wolfSSL/wolfssl/releases
- **NVD Entry:** hxxps[://]nvd[.]nist[.]gov/vuln/detail/CVE-2026-5194
- **Red Hat Advisory:** hxxps[://]access[.]redhat[.]com/security/cve/cve-2026-5194