XSS in Mybb

CVE-2021-27889

Cross-site Scripting (XSS) vulnerability in MyBB before 1.8.26 via Nested Auto URL when parsing messages.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.051 (91.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

  • Mybb
  • N/a — versions n/a

Weakness classification (CWE)

Public proof-of-concept exploits

References

  • cve@mitre.org (Patch, Third Party Advisory, x_refsource_MISC)
  • cve@mitre.org (Exploit, VDB Entry, Third Party Advisory, x_refsource_MISC)
  • cve@mitre.org (Exploit, Third Party Advisory, x_refsource_MISC)

Frequently asked questions

What is CVE-2021-27889?
CVE-2021-27889 is a medium-severity vulnerability in Mybb, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-03-15.
How severe is CVE-2021-27889?
Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2021-27889 known to be exploited?
5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.