HIGH
CVE-2021-30191
CWE-120Published: May 25, 2021· Updated: Jun 17, 2026
7.5
CVSS v3.1
Official Description
CODESYS V2 Web-Server before 1.1.9.20 has a a Buffer Copy without Checking the Size of the Input.
Technical Analysis
CVE-2021-30191 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
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
All References (4)
→
https://customers.codesys.com/index.phpPermissions Required · Vendor Advisory
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https://customers.codesys.com/index.phpPermissions Required · Vendor Advisory
Quick Facts
CVE IDCVE-2021-30191
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-120
CISA KEVNo
Affected2 vendor(s)
PublishedMay 25, 2021
Related CVEs (CWE-120)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-30191 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.