CVE-2021-43281 json
MyBB before 1.8.29 allows Remote Code Injection by an admin with the "Can manage settings?" permission.
published 2021-11-04 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-30225
- cvss
- 7.2
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.3%
- EPSS 1.3% chance of exploitation in 30 days, percentile 71%
- public exploits
- 0
- none known
Summary
MyBB before 1.8.29 allows Remote Code Injection by an admin with the "Can manage settings?" permission. The Admin CP's Settings management module does not validate setting types correctly on insertion and update, making it possible to add settings of supported type "php" with PHP code, executed on Change Settings pages.
Patch / fix
Exploit prediction
1.33% chance of exploitation in the next 30 days, higher than 71% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 7.2 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 6.5 | AV:N/AC:L/Au:S/C:P/I:P/A:P |
Classification
- Weakness
-
- CWE-94 Improper Control of Generation of Code
References
-
github.com
/mybb/mybb/security/advisories/GHSA-8gxx-vmr9-h39p
patch, release-notes, third-party-advisory
Sources
- CVE List CVE-2021-43281
- NVD CVE-2021-43281
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.