What’s Vulnerable › Vulnerabilities

CVE-2023-53976: myBB Forums 1.8.26 Stored Cross-Site Scripting via Template Management

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2025-12-22 · updated 2026-06-17
• Weakness: CWE-79

Description

myBB Forums 1.8.26 contains a stored cross-site scripting vulnerability in the template management system that allows authenticated administrators to inject malicious scripts when creating new templates. Attackers can exploit this vulnerability by inserting script payloads in the template title field when adding new templates through the 'Templates and Style' > 'Templates' > 'Manage Templates' > 'Global Templates' interface, causing arbitrary JavaScript to execute when the template is viewed.

Affected products

• mybb: 1.8.26

References

• https://mybb.com/
• https://www.exploit-db.com/exploits/51136
• https://www.vulncheck.com/advisories/mybb-forums-stored-cross-site-scripting-via-template-management
• https://www.cve.org/CVERecord?id=CVE-2021-41866

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