How severe is CVE-2021-21399?

CVE-2021-21399 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2021-21399 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21399?

CVE-2021-21399 affects Ampache. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21399?

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

When was CVE-2021-21399 published?

CVE-2021-21399 was published on 2021-04-13 and last updated on 2026-06-17.

CVE-2021-21399

CVE-2021-21399 is a critical-severity vulnerability in Ampache with a CVSS 3.x base score of 9.1. 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-287.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 5.0
EPSS exploit prediction: 1% (70th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Ampache
Published: 2021-04-13
Last modified: 2026-06-17

Description

Ampache is a web based audio/video streaming application and file manager. Versions prior to 4.4.1 allow unauthenticated access to Ampache using the subsonic API. To successfully make the attack you must use a username that is not part of the site to bypass the auth checks. For more details and workaround guidance see the referenced GitHub security advisory.

Frequently asked questions

What is CVE-2021-21399?: Ampache is a web based audio/video streaming application and file manager. Versions prior to 4.4.1 allow unauthenticated access to Ampache using the subsonic API. To successfully make the attack you must use a username that is not part of the site to bypass the auth checks. For more details and workaround guidance see the referenced GitHub security advisory.
How severe is CVE-2021-21399?: CVE-2021-21399 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2021-21399 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21399?: CVE-2021-21399 affects Ampache. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21399?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-21399 published?: CVE-2021-21399 was published on 2021-04-13 and last updated on 2026-06-17.

References

https://github.com/ampache/ampache/security/advisories/GHSA-p9pm-j95j-5mjf

Affected products (1)

cpe:2.3:a:ampache:ampache:*:*:*:*:*:*:*:*

More vulnerabilities in Ampache

CVE-2023-0771 — High (CVSS 8.8): SQL Injection in GitHub repository ampache/ampache prior to 5.5.7,develop.
CVE-2022-4665 — High (CVSS 8.8): Unrestricted Upload of File with Dangerous Type in GitHub repository ampache/ampache prior to 5.5.6.
CVE-2019-12385 — High (CVSS 8.8): An issue was discovered in Ampache through 3.9.1. The search engine is affected by a SQL Injection, so any user able to…
CVE-2017-18375 — High (CVSS 8.8): Ampache 3.8.3 allows PHP Object Instantiation via democratic.ajax.php and democratic.class.php.
CVE-2020-15153 — High (CVSS 8.2): Ampache before version 4.2.2 allows unauthenticated users to perform SQL injection. Refer to the referenced GitHub…
CVE-2024-51487 — High (CVSS 8.1): Ampache is a web based audio/video streaming application and file manager. The current implementation of token parsing…

All CVEs affecting Ampache →

Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-46389 — Critical (CVSS 10.0): UDS Identity Config builds the Keycloak configuration image (realm, plugins, theme, truststore, JARs) consumed by UDS…
CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

Browse all CWE-287 (Improper Authentication) vulnerabilities →