CVE-2021-42078

Name: CVE-2021-42078
Creator: NVD / NIST
Published: 2021-11-08T05:15:07.553+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.86%

Last modified Jun 17, 2026

CVE-2021-42078 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. PHP Event Calendar through 2021-11-04 allows persistent cross-site scripting (XSS), as demonstrated by the /server/ajax/events_manager.php title parameter. This can be exploited by an adversary in multiple ways, e.g., to perform actions on the page in the context of other users, or to deface the site.. EPSS estimates a 0.86% chance of exploitation in the next 30 days.

Description

PHP Event Calendar through 2021-11-04 allows persistent cross-site scripting (XSS), as demonstrated by the /server/ajax/events_manager.php title parameter. This can be exploited by an adversary in multiple ways, e.g., to perform actions on the page in the context of other users, or to deface the site.

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

0.86%

54.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Php Event Calendar Project	Php Event Calendar	2021-11-04

References

http://seclists.org/fulldisclosure/2021/Nov/24Exploit, Mailing List, Third Party Advisory
https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2021-049.txtExploit, Third Party Advisory
http://seclists.org/fulldisclosure/2021/Nov/24Exploit, Mailing List, Third Party Advisory
https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2021-049.txtExploit, Third Party Advisory

Timeline

Published: Nov 8, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-42078?

How severe is CVE-2021-42078?

CVE-2021-42078 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.86% probability of exploitation in the next 30 days.

How do I fix CVE-2021-42078?

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-2021-42078?

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

Scan your code now

Source: NVD / NIST