CVE-2021-21399Public exploitNetwork attack vector

Unauthenticated media access via nonexistent username token

Published Apr 13, 2021 · Updated Aug 3, 2024

Authentication bypass in Ampache before 4.4.1 allows remote attackers to access media through the Subsonic API without an account. Auth::token_check hashes a missing user's empty API-key result with attacker-supplied salt and accepts the matching token without validating the returned username and key. A nonexistent username is required; successful requests can read playlists and media through enabled Subsonic functions.

CVSS severity9.1
Critical
EPSS probability1.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Authentication bypass in Ampache before 4.4.1 allows remote attackers to access media through the Subsonic API without an account. Auth::token_check hashes a missing user's empty API-key result with attacker-supplied salt and accepts the matching token without validating the returned username and key. A nonexistent username is required; successful requests can read playlists and media through enabled Subsonic functions.

The record

CVE
CVE-2021-21399
Published
Apr 13, 2021
Updated
Aug 3, 2024
Vendor
Ampache
Product
Ampache
Classifications
CWE-287, CWE-284, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.4.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Ampache · Ampacheversion=< 4.4.1

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
9.1GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-287Improper Authentication
CWE-284Improper Access Control
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo