CVE-2026-127131
Deferred Deferred - Pending Action

SOGo TOTP Bypass via Missing Rate Limiting

Publication date: 2026-11-12

Last updated on: 2026-11-12

Assigner: VulnCheck

Description
SOGo before 5.12.13 contains a missing rate limiting vulnerability in its web login TOTP verification that allows attackers who already possess a victim's password to brute-force the second-factor code without triggering any lockout. Attackers can send repeated POST requests to /SOGo/connect with wrong verification codes at high speed since failed TOTP attempts never increment the failed-login counter and SOGoMaximumFailedLoginCount does not apply, enabling indefinite guessing across 30-second code windows to bypass two-factor authentication.

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Meta Information

Published
2026-11-12
Last Modified
2026-11-12
Generated
2026-11-12
AI Q&A
2026-11-12
EPSS Evaluated
N/A
NVD
CVE-2026-127131
EUVD
EUVD-2026-124530

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
Alinto sogo From 0 (inc) to 5.12.13 (exc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-307 The product does not implement sufficient measures to prevent multiple failed authentication attempts within a short time frame.

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Executive Summary

SOGo before version 5.12.13 has a missing rate limiting vulnerability in its web login TOTP verification. Attackers who already know a victim's password can brute-force the second-factor code by sending repeated POST requests to /SOGo/connect with wrong codes. Failed attempts do not trigger lockouts, allowing unlimited guesses within 30-second windows to bypass two-factor authentication.

Detection Guidance

To detect this vulnerability, monitor for repeated POST requests to /SOGo/connect with incorrect TOTP codes. Check web server logs for high-frequency login attempts targeting this endpoint. Implement rate limiting or intrusion detection rules to flag unusual activity.

Impact Analysis

If you use SOGo versions before 5.12.13, attackers with your password could bypass two-factor authentication and gain unauthorized access to your account. This could lead to data theft, unauthorized actions, or further compromise of your systems.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating compliance requirements for data protection like GDPR and HIPAA. Organizations may face penalties for failing to protect user data adequately.

Mitigation Strategies

Immediately upgrade SOGo to version 5.12.13 or later to patch the vulnerability. If upgrading is not possible, implement rate limiting on the /SOGo/connect endpoint and enforce account lockouts after a small number of failed TOTP attempts.

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