What’s Vulnerable › Vulnerabilities

CVE-2021-33563

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-05-24 · updated 2026-06-17
• Weakness: CWE-916

Description

Koel before 5.1.4 lacks login throttling, lacks a password strength policy, and shows whether a failed login attempt had a valid username. This might make brute-force attacks easier.

Affected products

• koel: before 5.1.4 — fixed in 5.1.4

How to fix

Upgrade to a fixed version: koel 5.1.4. Check the vendor advisory for mitigations.

References

• https://github.com/koel/koel/releases/tag/v5.1.4
• https://huntr.dev/bounties/1-other-koel/koel/
• https://github.com/koel/koel/releases/tag/v5.1.4
• https://huntr.dev/bounties/1-other-koel/koel/

Get alerted when CVE-2021-33563 or the next vulnerability affects your stack