What’s Vulnerable › Vulnerabilities

CVE-2023-53977: myBB Forums 1.8.26 Stored Cross-Site Scripting via Forum 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 forum management system that allows authenticated administrators to inject malicious scripts when creating new forums. Attackers can exploit this vulnerability by inserting script payloads in the forum title field when adding new forums through the 'Forums and Posts' > 'Forum Management' interface, causing arbitrary JavaScript to execute when the forum listing 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-forum-management

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