CVE-2021-41129Network attack vector

Authentication bypass via user-controlled 2FA token

Published Oct 6, 2021 · Updated Aug 4, 2024

Improper authentication in Pterodactyl Panel 1.0.0 through 1.6.1 allows remote attackers to access arbitrary user accounts via crafted 2FA tokens. LoginCheckpointController@__invoke accepts a confirmation_token that can be changed to a numeric cache key, loading another user_id before checking that account's two-factor token. Exploitation requires a target account with 2FA, a valid token that can be brute-forced without rate limiting, and a cache entry that remains valid; successful access can expose or alter that account's panel resources.

CVSS severity8.1
High
EPSS probability1.75%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in Pterodactyl Panel 1.0.0 through 1.6.1 allows remote attackers to access arbitrary user accounts via crafted 2FA tokens. LoginCheckpointController@__invoke accepts a confirmation_token that can be changed to a numeric cache key, loading another user_id before checking that account's two-factor token. Exploitation requires a target account with 2FA, a valid token that can be brute-forced without rate limiting, and a cache entry that remains valid; successful access can expose or alter that account's panel resources.

The record

CVE
CVE-2021-41129
Published
Oct 6, 2021
Updated
Aug 4, 2024
Vendor
Pterodactyl
Product
Pterodactyl Panel
Classifications
CWE-502, CWE-639, CWE-807, CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 6, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=>= 1.0.0, < 1.6.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Pterodactyl · Pterodactyl Panelversion=>= 1.0.0, < 1.6.2

Published CVSS scores

7.5NISTAV:N/AC:M/Au:N/C:P/I:P/A:P
8.1GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
CWE-639Authorization Bypass Through User-Controlled Key
CWE-807Reliance on Untrusted Inputs in a Security Decision
CWE-287Improper Authentication
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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