CVE-2021-27279
MyBB before 1.8.25 allows stored XSS via nested [email] tags with MyCode (aka BBCode).
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
MyBB before 1.8.25 allows stored XSS via nested [email] tags with MyCode (aka BBCode).
- Record
CVE-2021-27279- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - CVSS 2.0
- 3.5 Low
AV:N/AC:M/Au:S/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
CVE ListNo score
MyBB before 1.8.25 allows stored XSS via nested [email] tags with MyCode (aka BBCode).
- Record
CVE-2021-27279- Updated
- 2026-11-02
EUVDEUVD-2021-14044No score
MyBB before 1.8.25 allows stored XSS via nested [email] tags with MyCode (aka BBCode).
- Record
EUVD-2021-14044- Updated
- 2026-11-03
OSV
MyBB before 1.8.25 allows stored XSS via nested [email] tags with MyCode (aka BBCode).
- Record
CVE-2021-27279- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-27279 is a medium vulnerability (CVSS 5.4) in Mybb, published February 22, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.96%, the 61st percentile. No source names a fixed version.