CVE-2026-94418: WolfSSL certificate signature verification bypass under WOLFSSL_SMALL_CERT_VERIFY

CVE-2026-94418 · Severity: info · Published 2026-09-27

WolfSSL is a cryptographic library used in embedded systems and IoT devices to secure network communications. Under a specific configuration (WOLFSSL_SMALL_CERT_VERIFY), a flaw allows attackers to forge TLS certificates by bypassing signature validation when certain date-check overrides are enabled. An attacker can impersonate trusted servers without possessing valid credentials, potentially leading to session hijacking and data interception.

Technologies: Wolfssl. Vendors: Wolfssl.

Quick answers

Is CVE-2026-94418 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-94418 being exploited in the wild.
How severe is CVE-2026-94418?
Informational severity, published 27 September 2026.
Which products and versions are affected?
Wolfssl Affected when compiled with WOLFSSL_SMALL_CERT_VERIFY enabled.
Is there a fix for CVE-2026-94418?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-94418 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-94418?
Check whether you run Wolfssl at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

When WOLFSSL_SMALL_CERT_VERIFY is defined, ProcessPeerCertParse() separates certificate signature verification from parsing to reduce memory usage, but only returns the signature result when parsing succeeds. This inverts the validation precedence—date checks run after signature confirmation, allowing a custom verify callback that overrides date errors to hide signature failures. An attacker can present a self-signed certificate with the CA's name as issuer, arbitrary signature bytes, a past validity window, and their own key pair; no PKI material or CA compromise required.

Affected products

  • WolfSSL wolfSSL Affected when compiled with WOLFSSL_SMALL_CERT_VERIFY enabled

Timeline

  • 2026-09-27: disclosed
  • 2026-09-27: advisory: CVE-2026-94418

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