HOMEVULNERABILITIESCVE-2021-4236
CRITICAL

CVE-2021-4236

CWE-476Published: December 27, 2022· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official Description

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.

NVD Source

Technical Analysis

CVE-2021-4236 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

web_project1 product(s)
web
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/ecnepsnai/web/commit/5a78f8d5c41ce60dcf9f61aaf47a7a8dc3e0002f
PATCHhttps://pkg.go.dev/vuln/GO-2021-0107
PATCHhttps://github.com/ecnepsnai/web/commit/5a78f8d5c41ce60dcf9f61aaf47a7a8dc3e0002f
PATCHhttps://pkg.go.dev/vuln/GO-2021-0107

All References (4)

→
https://github.com/ecnepsnai/web/commit/5a78f8d5c41ce60dcf9f61aaf47a7a8dc3e0002fPatch · Third Party Advisory
→
https://pkg.go.dev/vuln/GO-2021-0107Exploit · Patch · Third Party Advisory
→
https://github.com/ecnepsnai/web/commit/5a78f8d5c41ce60dcf9f61aaf47a7a8dc3e0002fPatch · Third Party Advisory
→
https://pkg.go.dev/vuln/GO-2021-0107Exploit · Patch · Third Party Advisory

Quick Facts

CVE IDCVE-2021-4236
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-476
CISA KEVNo
Affected1 vendor(s)
PublishedDec 27, 2022

Related CVEs (CWE-476)

CVE-2010-2495
10.0
CVE-2022-36648
10.0
CVE-2017-17701
9.8
CVE-2017-17465
9.8
CVE-2017-17464
9.8
CVE-2017-17700
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-4236 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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