Cross-site Scripting Vulnerability in WPMU DEV Hummingbird Performance Plugin
CVE-2026-121763

6.5MEDIUM

Key Information:

Vendor

WordPress
Status
Hummingbird
Vendor
CVE Published:
9 November 2026

What is CVE-2026-121763?

A Cross-site Scripting (XSS) vulnerability exists in the WPMU DEV Hummingbird Performance plugin. This flaw allows attackers to inject malicious scripts into web pages generated by the plugin, resulting in the potential for stored XSS attacks. Impacted versions include all versions prior to 3.21.2, making it critical for users to upgrade to the latest version to safeguard their websites from potential exploitation.

Affected Version(s)

Hummingbird 0 <= 3.21.2

References

https://patchstack.com/database/wordpress/plugin/hummingb...
vdb-entry

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
Required
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

mroccon | Patchstack Bug Bounty Program
.