# CVE-2026-89136: wolfSSL TLS authentication bypass in Raw Public Key handling

Source: https://junglewise.ai/threats/cve-2026-89136-when-using-rpk-raw-public-key-the-client-side-of-a-tls-1-2-1-3  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-27. Updated: 2026-09-27  
License: CC BY 4.0 with a link back

CVE-2026-89136 · Severity: info · Published 2026-09-27

wolfSSL is a cryptography library used to secure TLS and DTLS connections. When Raw Public Key (RPK) authentication is enabled, a malicious server can bypass client-side authentication checks by sending an unsolicited certificate type, potentially allowing an attacker to impersonate a legitimate server. This vulnerability affects TLS 1.2, TLS 1.3, and DTLS 1.2 connections.

Technologies: [Wolfssl](https://junglewise.ai/threats/technologies/wolfssl). Vendors: [Wolfssl](https://junglewise.ai/threats/vendors/wolfssl).

## Quick answers

**Is CVE-2026-89136 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-89136 being exploited in the wild.

**How severe is CVE-2026-89136?** Informational severity, published 27 September 2026.

**Which products and versions are affected?** Wolfssl Prior to fix in PR #11009 (merged August 2026).

**Is there a fix for CVE-2026-89136?** 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-2026-89136 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-89136?** 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

The vulnerability exists in wolfSSL's TLS 1.2, 1.3, and DTLS 1.2 implementations when RPK support is compiled in. The client fails to properly validate the server_cert_type negotiation, allowing a misbehaving server to inject an unsolicited RawPublicKey certificate type and bypass authentication checks. The flaw is only present in builds compiled with --enable-rpk, --enable-all, or --enable-distro flags.

## Affected products

- wolfSSL wolfSSL Prior to fix in PR #11009 (merged August 2026)

## Timeline

- 2026-09-27: disclosed

## References

- [https://github.com/wolfSSL/wolfssl/pull/11009](https://github.com/wolfSSL/wolfssl/pull/11009)

## Related threats

- [wolfSSL certificate validation bypass in ConfirmNameConstraints()](https://junglewise.ai/threats/cve-2026-95208-an-issue-in-the-confirmnameconstraints-function-wolfcrypt-src-asn)
- [wolfSSL revocation check bypass with OCSP and CRL](https://junglewise.ai/threats/cve-2026-94417-when-an-application-enables-both-ocsp-and-crl-revocation-checking)
- [wolfSSL TLS 1.2 ChangeCipherSpec message ordering bypass](https://junglewise.ai/threats/cve-2026-93304-a-d-tls-1-2-client-can-accept-a-changecipherspec-message-before)
- [wolfSSL MatchTrustedPeer public key validation bypass](https://junglewise.ai/threats/cve-2026-93302-matchtrustedpeer-ignores-the-public-key-used-leading-to-forged-ca)
- [wolfSSL X509_verify_cert certificate validation bypass in CertManager](https://junglewise.ai/threats/cve-2026-89135-a-failed-x509-verify-cert-call-permanently-plants-an-unverified)