Mybb
CVE-2015-8976
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 6.1 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required. EPSS exploitation probability: 0.32%. |
| Exploit ScenarioDerived | A remote attacker could inject malicious scripts into web pages viewed by other users by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAI
Cross-site scripting (XSS) vulnerability in MyBB (aka MyBulletinBoard) before 1.6.18 and 1.8.x before 1.8.6 and MyBB Merge System before 1.8.6 might allow remote attackers to inject arbitrary web. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.
Affects your stack
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Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. Cross-site scripting (XSS) vulnerability in MyBB (aka MyBulletinBoard) before 1.6.18 and 1.8.x before 1.8.6 and MyBB Merge System before 1.8.6 might allow remote attackers to inject arbitrary web script or HTML via vectors related to "old upgrade files." Affected products include: Mybb Merge System, Mybb. Version information: before 1.6.18.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionCVE.org
Cross-site scripting (XSS) vulnerability in MyBB (aka MyBulletinBoard) before 1.6.18 and 1.8.x before 1.8.6 and MyBB Merge System before 1.8.6 might allow remote attackers to inject arbitrary web script or HTML via vectors related to "old upgrade files."
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.
Affected Products (CPE)CVE.org
MyBB is a free and open source forum software. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitabl
The installer in MyBB before 1.8.13 allows remote attackers to execute arbitrary code by writing to the configuration fi
SQL Injection vulnerability in MyBB before 1.8.26 via poll vote count. Rated high severity (CVSS 8.8), this vulnerabilit
SQL Injection vulnerablity in MyBB before 1.8.26 via theme properties included in theme XML files. Rated high severity (
In MyBB before 1.8.21, an attacker can exploit a parsing flaw in the Private Message / Post renderer that leads to [vide
Privilege escalation in MyBB 1.8.40 lets a limited Admin Control Panel (ACP) user who holds only the delegated user-mana
MyBB before 1.8.11 allows remote attackers to bypass an SSRF protection mechanism. Rated high severity (CVSS 7.7), this
SQL injection vulnerability in member.php in MyBB (aka MyBulletinBoard) 1.8.x before 1.8.2 allows remote attackers to ex
An issue in MyBB 1.8.38 allows a remote attacker to obtain sensitive information via the Change Avatar function. Rated h
An issue in MyBB 1.8.38 allows a remote attacker to obtain sensitive information via the Import a Theme function. Rated
An issue in MyBB 1.8.38 allows a remote attacker to obtain sensitive information via the Mail function. Rated high sever
Multiple SQL injection vulnerabilities in ajaxfs.php in the Ajax forum stat (Ajaxfs) Plugin 2.0 for MyBB (aka MyBulletin
GitHub PoC
Exploit-DB