XSS in Mybb

CVE-2021-27279

MyBB before 1.8.25 allows stored XSS via nested [email] tags with MyCode (aka BBCode).

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.010 (57.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

Affected products

Mybb
N/a — versions n/a

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

cve@mitre.org (x_refsource_MISC, Release Notes, Vendor Advisory)
cve@mitre.org (x_refsource_CONFIRM, Exploit, Third Party Advisory)
cve@mitre.org (x_refsource_CONFIRM, Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-27279?: CVE-2021-27279 is a medium-severity vulnerability in Mybb, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-02-22.
How severe is CVE-2021-27279?: Medium severity. CVSS v3 base score is 5.4 out of 10.