Improper Certificate Validation Affecting wolfSSL/wolfssh package, versions [,5.9.2)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-UNMANAGED-WOLFSSLWOLFSSH-17660712
- published28 Jun 2026
- disclosed25 Jun 2026
- creditUnknown
Introduced: 25 Jun 2026
CVE-2026-55964 (opens in a new tab)How to fix?
Upgrade wolfSSL/wolfssh to version 5.9.2 or higher.
Overview
Affected versions of this package are vulnerable to Improper Certificate Validation in the certificate path-building process when handling chain-supplied temporary CAs lacking the keyCertSign key usage extension. An attacker can cause acceptance of an unauthorized intermediate certificate as a signing CA by supplying a certificate chain where an intermediate CA asserts CA:TRUE but does not have the keyCertSign usage, potentially enabling unauthorized certificate signing. This is only exploitable if the OpenSSL-compatibility certificate-path-building path is used (such as X509_verify_cert / X509_STORE with OPENSSL_EXTRA/OPENSSL_ALL enabled), and the Key Usage extension is present in the certificate.