wolfSSL 5.9.4 Fixes Eleven TLS and Certificate Validation Flaws
Tech GuruQuick Answer
wolfSSL 5.9.4 fixes eleven vulnerabilities, but their applicability depends on the protocols, build options, APIs, and caches in use. Check the vendor's conditions for your build, then update the library or obtain a supported fixed firmware/application build. Replacing a shared library will not repair every statically linked copy.
Confirm Scope And Apply The Supported Fix
Next step: Identify the applications and devices that contain wolfSSL, record their build options and owners, and obtain the appropriate fixed release. Plan required process restarts and context or cache recreation using the vendor's instructions.
Last verified: 2026-09-27 UTC. Recheck the authoritative advisory and supported distribution channel before changing production.
Scope And Authority
| Product scope | wolfSSL releases through 5.9.2 under the CVE-specific protocol, API, feature, macro, and cache conditions |
|---|---|
| Advisory | wolfSSL 5.9.4 |
| CVEs | CVE-2026-15442, CVE-2026-89102, CVE-2026-89133, CVE-2026-89134, CVE-2026-89135, CVE-2026-89136, CVE-2026-93302, CVE-2026-93304, CVE-2026-94417, CVE-2026-94418, CVE-2026-94419 |
| Authoritative release date | 2026-09-25 (date stated by wolfSSL in the 5.9.4 release title; GitHub published the release at 2026-09-27 03:55:55 UTC) |
| Authority revision date | GitHub release metadata last updated 2026-09-27 03:57:54 UTC; wolfSSL does not label a separate material advisory revision |
| Affected versions | CVE-specific ranges through wolfSSL 5.9.2; applicability depends on the exact (D)TLS protocol, certificate workflow, API, build macro, callback, revocation, or session-cache conditions in the vendor release. |
| Fixed version | wolfSSL 5.9.4 |
| CVSS base score | 2.3 / 6.3 / 8.3 (CVSS v4.0) |
| CVSS severity | Low to High |
| Exploitation status | Not stated by the authority; no exploitation claim is inferred. |
What Changed
The fixes span certificate and trusted-peer handling, revocation checks, TLS/DTLS state, and session caching. The release also describes persistent-state implications for specific CVEs. Keep each condition attached to its CVE; neither a version string nor a default-build assumption settles all eleven questions.
What To Validate Now
- Inventory. Locate direct, statically linked, embedded, appliance, and transitive wolfSSL deployments; record the exact version, package origin, build macros, protocol modes, certificate APIs, revocation settings, verification callbacks, session-cache APIs, and accountable owners.
- Establish applicability. Use the vendor's per-CVE affected ranges and configuration preconditions. A wolfSSL version at or below 5.9.2 is not by itself proof that every listed flaw applies, and a default build is not affected by every item.
- Remediate. Upgrade affected deployments to wolfSSL 5.9.4 or a vendor-supported downstream build that demonstrably contains each applicable fix. If change cannot be immediate, apply only the CVE-specific vendor mitigation; for CVE-2026-93302 the release identifies disabling OpenSSL-compatible defaults and avoiding the trust-peer APIs as a mitigation.
- Validate. Check the library actually loaded by each consumer, then exercise the certificate, mutual-authentication, revocation, session-resumption, and shutdown paths that consumer uses. Test both valid connections and expected rejection of invalid certificates in isolation; record results rather than treating a successful handshake as complete validation.
- Retain evidence. Preserve asset and owner identifiers, the applicability decision, before-and-after versions, change approval, installation output, validation results, and any exception or rollback record.
Operational Cautions
Configuration preconditions differ substantially across the eleven CVEs. Replacing a library file may not update statically linked or embedded copies; CVE-2026-94417 and CVE-2026-94418 can leave persistent certificate-manager state, and CVE-2026-94419 changes the cache format. Follow the vendor's restart or cache-handling implications, preserve build provenance, and do not infer exploitation from severity.
Evidence To Retain
- Exact product, release stream, package or application version, enabled feature, environment, and accountable owner.
- UTC timestamps, authority revision, approved change record, installer or package-manager output, and resulting version.
- Relevant logs and monitoring evidence, test results, exceptions, compensating controls, and rollback decisions.
Related TechGeeks Resources
Authoritative References
Correction policy: If the authority changes affected versions, fixed versions, severity, exploitation information, mitigations, or required action, TechGeeks will update this notice and its verification date.
