What’s Vulnerable › Vulnerabilities

CVE-2019-12830

• Severity: high (CVSS 8.7 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2019-06-15 · updated 2026-06-17
• Weakness: CWE-79

Description

In MyBB before 1.8.21, an attacker can exploit a parsing flaw in the Private Message / Post renderer that leads to [video] BBCode persistent XSS to take over any forum account, aka a nested video MyCode issue.

Affected products

• mybb: before 1.8.21 — fixed in 1.8.21

How to fix

Upgrade to a fixed version: mybb 1.8.21. Check the vendor advisory for mitigations.

References

• https://blog.mybb.com/2019/06/10/mybb-1-8-21-released-security-maintenance-release/
• https://blog.ripstech.com/2019/mybb-stored-xss-to-rce/
• https://blog.mybb.com/2019/06/10/mybb-1-8-21-released-security-maintenance-release/
• https://blog.ripstech.com/2019/mybb-stored-xss-to-rce/

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