What’s Vulnerable › Vulnerabilities

CVE-2021-27949

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-03-15 · updated 2026-06-17
• Weakness: CWE-79

Description

Cross-site Scripting vulnerability in MyBB before 1.8.26 via Custom moderator tools.

Affected products

• mybb: before 1.8.26 — fixed in 1.8.26

How to fix

Upgrade to a fixed version: mybb 1.8.26. Check the vendor advisory for mitigations.

References

• https://github.com/mybb/mybb/security/advisories/GHSA-cmmr-39v8-8rx2
• https://github.com/mybb/mybb/security/advisories/GHSA-cmmr-39v8-8rx2

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