CVE-2021-21799

Name: CVE-2021-21799
Creator: NVD / NIST
Published: 2021-07-16T11:15:09.613+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 12.29%

Last modified Jun 17, 2026

CVE-2021-21799 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. Cross-site scripting vulnerabilities exist in the telnet_form.php script functionality of Advantech R-SeeNet v 2.4.12 (20.10.2020). If a user visits a specially crafted URL, it can lead to arbitrary JavaScript code execution in the context of the targeted user’s browser. EPSS estimates a 12.29% chance of exploitation in the next 30 days.

Description

Cross-site scripting vulnerabilities exist in the telnet_form.php script functionality of Advantech R-SeeNet v 2.4.12 (20.10.2020). If a user visits a specially crafted URL, it can lead to arbitrary JavaScript code execution in the context of the targeted user’s browser. An attacker can provide a crafted URL to trigger this vulnerability.

Metrics

CVSS 3.1

6.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS Probability

12.29%

95.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Advantech	R-Seenet	2.4.12

References

https://talosintelligence.com/vulnerability_reports/TALOS-2021-1270Exploit, Third Party Advisory
https://talosintelligence.com/vulnerability_reports/TALOS-2021-1270Exploit, Third Party Advisory

Timeline

Published: Jul 16, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21799?

How severe is CVE-2021-21799?

CVE-2021-21799 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 12.29% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21799?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-21799?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST