CVE-2026-55964 Vulnerability Analysis & Exploit Details

CVE-2026-55964
Vulnerability Scoring

Analysis In Progress
Analysis In Progress

Attack Complexity Details

  • Attack Complexity:
    Attack Complexity Analysis In Progress
  • Attack Vector:
    Attack Vector Under Analysis
  • Privileges Required: None
    No authentication is required for exploitation.
  • Scope:
    Impact is confined to the initially vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2026-55964 Details

Status: Undergoing Analysis

Published on: 25 Jun 2026, 20:17 UTC

CVSS Release:

CVE-2026-55964 Vulnerability Summary

CVE-2026-55964: Chain intermediate CA:TRUE without keyCertSign accepted as a signing CA. Intermediate CA certificates are required to have the keyCertSign key usage when a Key Usage extension is present, but chain-supplied temporary CAs (WOLFSSL_TEMP_CA) added while building a certificate path were previously exempted from this check, so an intermediate asserting CA:TRUE but lacking keyCertSign was accepted as a signing CA. The check now applies to chain-supplied temporary CAs as well; only operator-loaded root certificates (WOLFSSL_USER_CA) and self-signed roots remain exempt. Per RFC 5280 an absent Key Usage extension implies all usages, so the requirement is enforced only when the extension is actually present (extKeyUsageSet). Affects the OpenSSL-compatibility certificate-path-building path (X509_verify_cert / X509_STORE, OPENSSL_EXTRA/OPENSSL_ALL), where untrusted chain intermediates are added as temporary CAs; native (non-OpenSSL-compat) certificate verification does not create temporary CAs and is unaffected. Within those builds, the check applies unless ALLOW_INVALID_CERTSIGN is defined.

Assessing the Risk of CVE-2026-55964

Access Complexity Graph

The exploitability of CVE-2026-55964 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-55964

No exploitability data is available for CVE-2026-55964.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-55964, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-55964, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2026-55964 does not compromise confidentiality.
  • Integrity: None
    CVE-2026-55964 does not impact data integrity.
  • Availability: None
    CVE-2026-55964 does not affect system availability.

CVE-2026-55964 References

External References

CWE Common Weakness Enumeration

CWE-295

CAPEC Common Attack Pattern Enumeration and Classification

  • Creating a Rogue Certification Authority Certificate CAPEC-459 An adversary exploits a weakness resulting from using a hashing algorithm with weak collision resistance to generate certificate signing requests (CSR) that contain collision blocks in their "to be signed" parts. The adversary submits one CSR to be signed by a trusted certificate authority then uses the signed blob to make a second certificate appear signed by said certificate authority. Due to the hash collision, both certificates, though different, hash to the same value and so the signed blob works just as well in the second certificate. The net effect is that the adversary's second X.509 certificate, which the Certification Authority has never seen, is now signed and validated by that Certification Authority.
  • Signature Spoofing by Improper Validation CAPEC-475 An adversary exploits a cryptographic weakness in the signature verification algorithm implementation to generate a valid signature without knowing the key.

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