CVE-2021-43281

7.2 HIGH 1% exploit odds Fix listed

What it is

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.

At a glance

Exploitability: Can be exploited over the network with an admin-level account. High risk of data exposure, data tampering, service disruption.
Exploit odds: 1.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2021-11-04 18:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 04:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 1.3% in the next 30 days (EPSS).
Severity: 7.2 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2021-11-04 18:15 UTC
Last modified: 2026-06-17 04:10 UTC
Exploit probability: 1.3% · EPSS, next 30 days
Weakness: CWE-94 · Code injection
Record status: Modified

Affected

Mybb < 1.8.29

Attack profile CVSS 3.1 · 7.2

Attack vector: Network
Complexity: Low
Privileges needed: High
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-43281.md and follow it. Check whether this project is affected by CVE-2021-43281. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record