What is CVE-2017-8103?

CVE-2017-8103 is a medium-severity vulnerability in Mybb, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2017-04-24.

How severe is CVE-2017-8103?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Mybb

CVE-2017-8103

In MyBB before 1.8.11, the Email MyCode component allows XSS, as demonstrated by an onmouseover event.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2017-04-24 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.007 (51.8th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 51.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Mybb

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

seclists.org/fulldisclosure/2017/Apr/53 (VDB Entry, Third Party Advisory)
blog.mybb.com/2017/04/04/mybb-1-8-11-merge-system-1-8-11-release/ (Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2017-8103?: CVE-2017-8103 is a medium-severity vulnerability in Mybb, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2017-04-24.
How severe is CVE-2017-8103?: Medium severity. CVSS v3 base score is 6.1 out of 10.