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Vulnerability record · CVE-2023-53978 · published 22 December 2025

CVE-2023-53978: Mybb cross-site scripting vulnerability

Mybb · Mybb

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.

5.1 CVSS 4.0 Medium EPSS 0.24% · top 86.7% CWE-79 · Cross-site scripting
5.1CVSS 4.0 base score
0.24%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

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.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://mybb.com/ Product
https://www.exploit-db.com/exploits/51136 Exploit
https://www.vulncheck.com/advisories/mybb-forums-stored-cross-site-scripting-via-forum-announcements ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2011-10018Mybb code injection vulnerabilitymyBB version 1.6.4 was distributed with an unauthorized backdoor embedded in the source code. The backdoor allowed remote attackers to execute arbitr…EPSS 2.8%10.0CVE-2015-8974Mybb merge system sql injection vulnerabilitySQL injection vulnerability in the Group Promotions module in the admin control panel in MyBB (aka MyBulletinBoard) before 1.6.18 and 1.8.x before 1.…EPSS 2.1%10.0CVE-2015-2786Mybb vulnerabilityUnspecified vulnerability in MyBB (aka MyBulletinBoard) before 1.8.4 has unknown attack vectors related to "Group join request notifications sent to …EPSS 1.4%10.0CVE-2011-5133Mybb vulnerabilityUnspecified vulnerability in MyBB before 1.6.5 has unknown impact and attack vectors, related to an "unparsed user avatar in the buddy list."EPSS 1.7%10.0CVE-2006-0218Mybb vulnerabilityMultiple unspecified vulnerabilities in MyBulletinBoard (MyBB) before 1.0.2 have unspecified impact and attack vectors, related to (1) admin/moderate…EPSS 1.2%9.8CVE-2020-22612Mybb code injection vulnerabilityInstaller RCE on settings file write in MyBB before 1.8.22.EPSS 0.73%9.8CVE-2017-16780Mybb cross-site request forgery vulnerabilityThe installer in MyBB before 1.8.13 allows remote attackers to execute arbitrary code by writing to the configuration file.EPSS 5.8%9.8CVE-2016-9416Mybb merge system sql injection vulnerabilitySQL injection vulnerability in the users data handler in MyBB (aka MyBulletinBoard) before 1.8.8 and MyBB Merge System before 1.8.8 allows remote att…EPSS 2.1%

Source: NIST National Vulnerability Database (record CVE-2023-53978), CISA KEV, FIRST EPSS (scores of 2026-10-04). This page is refreshed as NVD updates the record.