CVE-2021-42077

Name: CVE-2021-42077
Creator: NVD / NIST
Published: 2021-11-08T04:15:08.683+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 2.43%

Last modified Jun 17, 2026

CVE-2021-42077 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. PHP Event Calendar before 2021-09-03 allows SQL injection, as demonstrated by the /server/ajax/user_manager.php username parameter. This can be used to execute SQL statements directly on the database, allowing an adversary in some cases to completely compromise the database system. EPSS estimates a 2.43% chance of exploitation in the next 30 days.

Description

PHP Event Calendar before 2021-09-03 allows SQL injection, as demonstrated by the /server/ajax/user_manager.php username parameter. This can be used to execute SQL statements directly on the database, allowing an adversary in some cases to completely compromise the database system. It can also be used to bypass the login form.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

2.43%

82.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-89

Affected Software

Vendor	Product	Versions
Kaysongroup	Php Event Calendar	< 2021-09-03

References

http://packetstormsecurity.com/files/164777/PHP-Event-Calendar-Lite-Edition-SQL-Injection.htmlExploit, Third Party Advisory, VDB Entry
https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2021-048.txtExploit, Third Party Advisory
http://packetstormsecurity.com/files/164777/PHP-Event-Calendar-Lite-Edition-SQL-Injection.htmlExploit, Third Party Advisory, VDB Entry
https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2021-048.txtExploit, Third Party Advisory

Timeline

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

Frequently Asked Questions

What is CVE-2021-42077?

How severe is CVE-2021-42077?

CVE-2021-42077 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 2.43% probability of exploitation in the next 30 days.

How do I fix CVE-2021-42077?

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-2021-42077?

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

Scan your code now

Source: NVD / NIST