What is CVE-2018-17128?

CVE-2018-17128 is a medium-severity vulnerability in Mybb, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2018-09-17.

How severe is CVE-2018-17128?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Mybb

CVE-2018-17128

A Persistent XSS issue was discovered in the Visual Editor in MyBB before 1.8.19 via a Video MyCode.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2018-09-17 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.748 (99.5th percentile), scored 2026-10-28.

High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.748 · newest: 0.748 · change: 0.000

Affected products

Mybb

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

blog.mybb.com/2018/09/11/mybb-1-8-19-released-security-maintenance-release/ (Release Notes, Vendor Advisory)
www.exploit-db.com/exploits/45449/ (Exploit, VDB Entry, Third Party Advisory, exploit)

Frequently asked questions

What is CVE-2018-17128?: CVE-2018-17128 is a medium-severity vulnerability in Mybb, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2018-09-17.
How severe is CVE-2018-17128?: Medium severity. CVSS v3 base score is 5.4 out of 10.