XSS in Mybb Timeline Plugin
CVE-2021-47934
MyBB Timeline Plugin 1.0 contains cross-site scripting vulnerabilities that allow attackers to inject malicious scripts through thread titles, post content, and user profile fields like Location and Bio. Attackers can also exploit a cross-site request forgery vulnerability in the timeline.php profile action to change a user's cover picture by crafting malicious forms that execute when victims visit affected profiles.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (12.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 13th percentile — 12.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
- Mybb Timeline Plugin — versions 1.0
Weakness classification (CWE)
References
- www.exploit-db.com/exploits/49467 (exploit)
- community.mybb.com/mods.php (product)
- www.vulncheck.com/advisories/mybb-timeline-plugin-cross-site-scripting-and-csrf (third-party-advisory)
Frequently asked questions
- What is CVE-2021-47934?
- CVE-2021-47934 is a medium-severity vulnerability in Mybb Timeline Plugin, classified under Cross-site Scripting. CVSS score: 5.3/10. Published 2026-05-16.
- How severe is CVE-2021-47934?
- Medium severity. CVSS v3 base score is 5.3 out of 10.