CVE-2026-42011

# PoC Concept for CVE-2026-42011 # This demonstrates the verification bypass logic. import subprocess def check_vulnerability(): # In a real scenario, this would involve generating a CA with excluded constraints # and a leaf certificate that should be rejected but is accepted. # Example command to simulate verification (conceptual) # If gnutls-cli validates a cert that violates implied constraints, it is vulnerable. print("Testing GnuTLS Name Constraint Bypass...") # Simulation: CA has excluded: .internal # Attacker cert: secure.internal # Expected: Reject (Secure) # Vulnerable Result: Accept (Exploited) print("Vulnerability allows bypassing name constraint checks when CA only has excluded constraints.") if __name__ == "__main__": check_vulnerability()

{"cve": {"id": "CVE-2026-42011", "sourceIdentifier": "[email protected]", "published": "2026-05-07T15:16:09.760", "lastModified": "2026-05-07T15:48:55.550", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "A flaw was found in gnutls. This vulnerability occurs because permitted name constraints were incorrectly ignored when previous Certificate Authorities (CAs) only had excluded name constraints. A remote attacker could exploit this to bypass critical name constraint checks during certificate validation. This bypass could lead to the acceptance of invalid certificates, potentially enabling spoofing or man-in-the-middle attacks against affected systems."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "baseScore": 7.4, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.2, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-295"}]}], "references": [{"url": "https://access.redhat.com/security/cve/CVE-2026-42011", "source": "[email protected]"}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2467437", "source": "[email protected]"}]}}