HOMEVULNERABILITIESCVE-2021-3351
MEDIUM

CVE-2021-3351

CWE-79Published: August 2, 2021· Updated: Jun 17, 2026

5.4
CVSS v3.1

Official Description

OpenPLC runtime V3 through 2016-03-14 allows stored XSS via the Device Name to the web server's Add New Device page.

NVD Source

Technical Analysis

CVE-2021-3351 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.

From a weakness classification perspective (CWE-79): Cross-site scripting (XSS) vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.Low
User InteractionRequired
ScopeChanged
Impact
ConfidentialityLow
IntegrityLow
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected Vendors & Products

openplcproject1 product(s)
openplc
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

All References (2)

https://www.youtube.com/watch?v=eSAqXq4m8soExploit · Third Party Advisory
https://www.youtube.com/watch?v=eSAqXq4m8soExploit · Third Party Advisory

Quick Facts

CVE IDCVE-2021-3351
CVSS Score5.4 / 10
SeverityMEDIUM
WeaknessCWE-79
CISA KEVNo
Affected1 vendor(s)
PublishedAug 2, 2021

Related CVEs (CWE-79)

Recommended Actions

  • Apply vendor patches immediately
  • Monitor CVE-2021-3351 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. CVE data is provided under the NVD usage policy.