GHSA-r37h-j483-cjjm: phanan/koel (CVE-2021-33563)

Improper rate limiting in Koel

No CVSS scoreEPSS 0.0081 · 57th percentile

Published by the GitHub Advisory Database at 1 Jun 2021, 21:38 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

Package	Ecosystem	Affected	Fixed in
phanan/koel	Packagist	<5.1.4	5.1.4

Identifiers

GHSA-r37h-j483-cjjm · CVE-2021-33563 · PKSA-929f-gr4s-2fz1

Weakness (CWE)

CWE-799 · CWE-916

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Koel versions before 5.1.4 lack login throttling and a password strength policy, and failed login attempts reveal whether a username is valid. An attacker with network access to the login page could use this to make brute-force guessing of passwords easier. Upgrade to Koel 5.1.4 or later, which is the listed fixed version.

Written 4 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

No source has published a CVSS score for this record yet.

CISA KEV Not listed.
EPSS 0.0081, the 57th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:28 UTC First seen by agentprime
31 Oct 2026, 14:28 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.