HOMEVULNERABILITIESCVE-2021-33824
HIGH

CVE-2021-33824

CWE-400Published: June 18, 2021· Updated: Jun 17, 2026

7.5
CVSS v3.1

Official Description

An issue was discovered on MOXA Mgate MB3180 Version 2.1 Build 18113012. Attackers can use slowhttptest tool to send incomplete HTTP request, which could make server keep waiting for the packet to finish the connection, until its resource exhausted. Then the web server is denial-of-service.

NVD Source

Technical Analysis

CVE-2021-33824 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 availability disruption (denial of service), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

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

Affected Vendors & Products

moxa2 product(s)
mgate mb3180 firmwaremgate mb3180
Source: NVD CPE · 2 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

ADVISORYhttps://github.com/Jian-Xian/CVE-POC/blob/master/CVE-2021-33824.md
ADVISORYhttps://github.com/shekyan/slowhttptest
ADVISORYhttps://www.moxa.com/en/products/industrial-edge-connectivity/protocol-gateways/modbus-tcp-gateways/mgate-mb3180-mb3280-mb3480-series
ADVISORYhttps://github.com/Jian-Xian/CVE-POC/blob/master/CVE-2021-33824.md
ADVISORYhttps://github.com/shekyan/slowhttptest
ADVISORYhttps://www.moxa.com/en/products/industrial-edge-connectivity/protocol-gateways/modbus-tcp-gateways/mgate-mb3180-mb3280-mb3480-series

All References (6)

→
https://github.com/Jian-Xian/CVE-POC/blob/master/CVE-2021-33824.mdExploit · Third Party Advisory
→
https://github.com/shekyan/slowhttptestThird Party Advisory
→
https://www.moxa.com/en/products/industrial-edge-connectivity/protocol-gateways/modbus-tcp-gateways/mgate-mb3180-mb3280-mb3480-seriesProduct · Vendor Advisory
→
https://github.com/Jian-Xian/CVE-POC/blob/master/CVE-2021-33824.mdExploit · Third Party Advisory
→
https://github.com/shekyan/slowhttptestThird Party Advisory
→
https://www.moxa.com/en/products/industrial-edge-connectivity/protocol-gateways/modbus-tcp-gateways/mgate-mb3180-mb3280-mb3480-seriesProduct · Vendor Advisory

Quick Facts

CVE IDCVE-2021-33824
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-400
CISA KEVNo
Affected1 vendor(s)
PublishedJun 18, 2021

Related CVEs (CWE-400)

CVE-2024-36543
9.8
CVE-2023-30769
9.8
CVE-2019-10750
9.8
CVE-2026-30141
9.8
CVE-2019-10747
9.8
CVE-2022-48716
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-33824 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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