CVE-2006-6421
NVD-CWE-OtherPublished: December 10, 2006· Updated: Jun 16, 2026
Official Description
Cross-site scripting (XSS) vulnerability in the private message box implementation (privmsg.php) in phpBB 2.0.x allows remote authenticated users to inject arbitrary web script or HTML via the "Message body" field in a message to a non-existent user.
Technical Analysis
CVE-2006-6421 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A proof-of-concept (PoC) exploit exists for CVE-2006-6421. While not yet confirmed in active campaigns, the availability of PoC code increases exploitation risk substantially.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
All References (20)
Quick Facts
Related CVEs (NVD-CWE-Other)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2006-6421 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts