CVE-2023-53978

MEDIUM 5.4

myBB Forums 1.8.26 Stored Cross-Site Scripting via Forum Announcements

CVSS Score

5.4

EPSS Score

0.0%

EPSS Percentile

0th

myBB Forums 1.8.26 contains a stored cross-site scripting vulnerability in the forum announcement system that allows authenticated administrators to inject malicious scripts when creating announcements. Attackers can exploit this vulnerability by inserting script payloads in the announcement title field when adding announcements through the 'Forums and Posts' > 'Forum Announcements' interface, causing arbitrary JavaScript to execute when the announcement is displayed on the forum.

CWE	CWE-79
Vendor	mybb
Product	mybb forums
Published	Dec 22, 2025
Last Updated	Apr 7, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Affected Versions

Mybb / myBB forums

1.8.26

References

NVD ↗ CVE.org ↗ EPSS Data ↗

exploit-db.com: https://www.exploit-db.com/exploits/51136 mybb.com: https://mybb.com/ vulncheck.com: https://www.vulncheck.com/advisories/mybb-forums-stored-cross-site-scripting-via-forum-announcements

Credits

Andrey Stoykov