CVE-2021-27279
MEDIUMCVSS 5.4/10EPSS 0.96%
Last modified
CVE-2021-27279 is a medium-severity vulnerability rated 5.4/10 on the CVSS scale. MyBB before 1.8.25 allows stored XSS via nested [email] tags with MyCode (aka BBCode).. EPSS estimates a 0.96% chance of exploitation in the next 30 days.
Description
MyBB before 1.8.25 allows stored XSS via nested [email] tags with MyCode (aka BBCode).
Metrics
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Mybb | Mybb | < 1.8.25 |
References
- https://github.com/mybb/mybb/commit/cb781b49116bf5c4d8deca3e17498122b701677aPatch, Third Party Advisory
- https://github.com/mybb/mybb/security/advisories/GHSA-6483-hcpp-p75wExploit, Third Party Advisory
- https://mybb.com/versions/1.8.25/Release Notes, Vendor Advisory
- https://github.com/mybb/mybb/commit/cb781b49116bf5c4d8deca3e17498122b701677aPatch, Third Party Advisory
- https://github.com/mybb/mybb/security/advisories/GHSA-6483-hcpp-p75wExploit, Third Party Advisory
- https://mybb.com/versions/1.8.25/Release Notes, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-27279?
MyBB before 1.8.25 allows stored XSS via nested [email] tags with MyCode (aka BBCode).
How severe is CVE-2021-27279?
CVE-2021-27279 has a CVSS score of 5.4/10 (MEDIUM severity). The EPSS model estimates a 0.96% probability of exploitation in the next 30 days.
How do I fix CVE-2021-27279?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2021-27279?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST