How severe is CVE-2021-33563?

CVE-2021-33563 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-33563 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-33563?

CVE-2021-33563 affects Koel. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-33563?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-33563 published?

CVE-2021-33563 was published on 2021-05-24 and last updated on 2026-06-17.

CVE-2021-33563

CVE-2021-33563 is a high-severity vulnerability in Koel with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-916.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (52nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-916
Affected product: Koel
Published: 2021-05-24
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-33563?: 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.
How severe is CVE-2021-33563?: CVE-2021-33563 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-33563 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-33563?: CVE-2021-33563 affects Koel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-33563?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-33563 published?: CVE-2021-33563 was published on 2021-05-24 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:koel:koel:*:*:*:*:*:*:*:*

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