What’s Vulnerable › Vulnerabilities

CVE-2021-34667: Calendar_plugin <= 1.0 Reflected Cross-Site Scripting

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-08-16 · updated 2026-06-17
• Weakness: CWE-79

Description

The Calendar_plugin WordPress plugin is vulnerable to Reflected Cross-Site Scripting due to the use of `$_SERVER['PHP_SELF']` in the ~/calendar.php file which allows attackers to inject arbitrary web scripts, in versions up to and including 1.0.

Affected products

• Calendar_plugin: through 1.0

References

• https://plugins.trac.wordpress.org/browser/calendar-plugin/trunk/calendar.php#L86
• https://www.wordfence.com/vulnerability-advisories/#CVE-2021-34667
• https://plugins.trac.wordpress.org/browser/calendar-plugin/trunk/calendar.php#L86
• https://www.wordfence.com/vulnerability-advisories/#CVE-2021-34667

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