CVE-2021-4236
CRITICALDescription
Web Sockets do not execute any AuthenticateMethod methods which may be set, leading to a nil pointer dereference if the returned UserData pointer is assumed to be non-nil, or authentication bypass. This issue only affects WebSockets with an AuthenticateMethod hook. Request handlers that do not explicitly use WebSockets are not vulnerable.
How to fix
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Moderate risk: more likely to be exploited than 62% of all known CVEs.
References
Related Vulnerabilities
Other CWE-476 (NULL Pointer Dereference) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-21758 | High | 7.5 | 92% | - | Fix |
| CVE-2023-21547 | High | 7.5 | 88% | - | Fix |
| CVE-2014-3470 | Medium | 4.3 | 86% | - | Fix |
| CVE-2021-44224 | High | 8.2 | 82% | - | Fix |
| CVE-2016-0742 | High | 7.5 | 82% | - | Fix |
| CVE-2009-1386 | Medium | 5.0 | 80% | - | Fix |
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Markdown
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-04-11.