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CVE-2021-33563

24
FAUCET Score

CVE-2021-33563 affects Koel versions prior to 5.1.4, stemming from a lack of login throttling, password strength policy, and username enumeration. This vulnerability allows unauthenticated attackers to remotely determine valid usernames and facilitates brute-force attacks. With a CVSS score of 7.5 (HIGH), it poses a significant risk for unauthorized access to sensitive information. There is currently no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 5.1.4CPE matchmatch criteria
cpe:2.3:a:koel:koel:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.79%
Probability of exploitation in next 30 days
EPSS Percentile
52.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0079 is in the 28th percentile among its peer group of 51,551 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

composerpatch availablevia ghsa
Product: phanan/koelFixed in: 5.1.4

Vendor Advisories (1)

composerGHSA-r37h-j483-cjjmhigh

Improper rate limiting in Koel

Jun 1, 2021

References

github.com / koel/koel/releases/tag/v5.1.4
Third Party Advisory
huntr.dev / bounties/1-other-koel/koel
ExploitIssue TrackingThird Party Advisory