What is CVE-2021-27946?

CVE-2021-27946 is a high-severity vulnerability in Mybb, classified under SQL Injection. CVSS score: 8.8/10. Published 2021-03-15.

How severe is CVE-2021-27946?

High severity. CVSS v3 base score is 8.8 out of 10.

SQL Injection in Mybb

CVE-2021-27946

SQL Injection vulnerability in MyBB before 1.8.26 via poll vote count. (issue 1 of 3).

Vulnerability class: SQL Injection

Published 2021-03-15 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.042 (90.6th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 91st percentile — 90.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.042 · newest: 0.042 · change: 0.000

Affected products

Mybb

Weakness classification (CWE)

CWE-89 — SQL Injection

References

github.com/mybb/mybb/security/advisories/GHSA-23m9-w75q-ph4p (Patch, Third Party Advisory, Release Notes)
packetstormsecurity.com/files/161918/MyBB-1.8.25-SQL-Injection.html (Exploit, VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2021-27946?: CVE-2021-27946 is a high-severity vulnerability in Mybb, classified under SQL Injection. CVSS score: 8.8/10. Published 2021-03-15.
How severe is CVE-2021-27946?: High severity. CVSS v3 base score is 8.8 out of 10.