# CVE-2026-55962: wolfSSL improper authentication in TLS 1.3 post-handshake authentication

Source: https://junglewise.ai/threats/cve-2026-55962-wolfssl-improper-authentication-in-tls-1-3-post-handshake  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-25. Updated: 2026-06-25  
License: CC BY 4.0 with a link back

CVE-2026-55962 · Severity: info · CVSS 6 · Published 2026-06-25

wolfSSL is a security library used to protect communications for embedded devices and cloud services. A vulnerability in its TLS 1.3 implementation could allow a client to bypass identity verification during a 'post-handshake' request for a certificate. This means an attacker could potentially maintain a secure connection without providing the required credentials, though it only affects specific configurations where the server requests a certificate after the initial connection is established.

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

## Quick answers

**Is CVE-2026-55962 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-55962 being exploited in the wild.

**How severe is CVE-2026-55962?** Informational severity, with a CVSS score of 6, published 25 June 2026.

**Which products and versions are affected?** Wolfssl 5.5.4 through 5.9.1.

**Is there a fix for CVE-2026-55962?** A patch was published on 2026-06-17: Fix merged into master branch via PR 10702 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-55962 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-55962?** 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

A vulnerability exists in wolfSSL's TLS 1.3 post-handshake authentication (PHA) logic. The server incorrectly applies an exemption intended only for the initial handshake, allowing it to accept a 'Finished' message even if the client fails to provide a 'Certificate' and 'CertificateVerify' message in response to a post-handshake 'CertificateRequest'. This occurs when WOLFSSL_POST_HANDSHAKE_AUTH is enabled and wolfSSL_request_certificate() is called. An attacker with an established TLS 1.3 session could bypass mandatory client authentication during the PHA phase. The issue is resolved in version 5.9.1 by ensuring the server enforces certificate requirements once a post-handshake request is outstanding.

## Affected products

- wolfSSL wolfSSL 5.5.4 through 5.9.1

## Timeline

- 2026-06-17: patched: Fix merged into master branch via PR 10702
- 2026-06-25: advisory: NVD publication date

## References

- [https://github.com/wolfSSL/wolfssl](https://github.com/wolfSSL/wolfssl)
- [https://github.com/wolfSSL/wolfssl/pull/10702](https://github.com/wolfSSL/wolfssl/pull/10702)
- [https://www.wolfssl.com/docs/security-vulnerabilities/](https://www.wolfssl.com/docs/security-vulnerabilities/)

## 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 TLS authentication bypass in Raw Public Key handling](https://junglewise.ai/threats/cve-2026-89136-when-using-rpk-raw-public-key-the-client-side-of-a-tls-1-2-1-3)