CVE-2025-64102: Zitadel allows brute-forcing authentication factors
Summary
A vulnerability in Zitadel allowed brute-force attack on OTP, TOTP and password allowing to impersonate the attacked user.
Impact
An attacker can perform an online brute-force attack on OTP, TOTP, and passwords. While Zitadel allows preventing online brute force attacks in scenarios like TOTP, Email OTP, or passwords using a lockout mechanism. The mechanism is not enabled by default and can cause a denial of service for the corresponding user if enabled. Additionally, the mitigation strategies were not fully implemented in the more recent resource-based APIs.
Affected Versions
All versions within the following ranges, including release candidates (RCs), are affected: - 4.x: 4.0.0 to 4.4.0 (including RC versions) - 3.x: 3.0.0 to 3.4.2 (including RC versions) - 2.x: v2.0.0 to 2.71.17
Patches
The vulnerability has been addressed in the latest releases. The patch resolves the issue by enforcing the lockout policy on all OTP, TOTP and password checks. Additionally a “tar pit” has been introduced to slow down brute-force attacks by default. Zitadel responses will be delayed by t seconds, where t increases over the number of failed attempts within a given timeframe.
4.x: Upgrade to >=4.6.0 3.x: Update to >=3.4.3 2.x: Update to >=2.71.18
Workarounds
The recommended solution is to update Zitadel to a patched version.
The problem might be mitigated by enabling the optional logout policy ("Password maximum attempts") or by implementing more strict rate limits.
Questions
If you have any questions or comments about this advisory, please email us at security@zitadel.com
Credits
This vulnerability was found by zentrust partners GmbH during a scheduled penetration test. Thank you to the analysts Martin Tschirsich, Joud Zakharia, Christopher Baumann. The full report will be made public after the complete review.
Other sources
Zitadel is open-source identity infrastructure software. Prior to 4.6.0, 3.4.3, and 2.71.18, an attacker can perform an online brute-force attack on OTP, TOTP, and passwords. While Zitadel allows preventing online brute force attacks in scenarios like TOTP, Email OTP, or passwords using a lockout mechanism. The mechanism is not enabled by default and can cause a denial of service for the corresponding user if enabled. Additionally, the mitigation strategies were not fully implemented in the more recent resource-based APIs. This vulnerability is fixed in 4.6.0, 3.4.3, and 2.71.18.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2025-64102?
CVE-2025-64102 is a critical vulnerability allowing online brute-force attacks on OTP and passwords in Zitadel.
How do I fix CVE-2025-64102?
To fix CVE-2025-64102, upgrade Zitadel to versions 4.6.0, 3.4.3, or 2.71.18 or later.
What types of attacks are possible with CVE-2025-64102?
CVE-2025-64102 allows an attacker to perform online brute-force attacks on One-Time Passwords (OTPs), Time-based One-Time Passwords (TOTP), and passwords.
Which versions of Zitadel are affected by CVE-2025-64102?
Versions of Zitadel prior to 4.6.0, 3.4.3, and 2.71.18 are affected by CVE-2025-64102.
Is there a workaround for CVE-2025-64102?
Implementing rate limiting or account lockout policies can help mitigate the risk of CVE-2025-64102 until an upgrade is performed.