What’s Vulnerable › Vulnerabilities

CVE-2026-100678: stoatchat before 0.15.5 MFA Brute Force via Insufficient Rate Limiting

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-26 · updated 2026-09-30
• Weakness: CWE-307

Description

stoatchat before 0.15.5 fails to enforce account-level attempt limits on MFA login challenges, allowing attackers who know a password to guess TOTP codes with only IP-based rate limiting. Attackers can reuse MFA challenge tickets across multiple failed attempts and distribute guesses across IP addresses to bypass rate limiting and gain account access.

Affected products

• stoatchat: before 0.15.5 — fixed in 0.15.5

How to fix

Upgrade to a fixed version: stoatchat 0.15.5. Check the vendor advisory for mitigations.

References

• https://github.com/stoatchat/stoatchat/security/advisories/GHSA-6877-g673-f5r8
• https://www.vulncheck.com/advisories/stoatchat-before-0.15.5-mfa-brute-force-via-insufficient-rate-limiting
• https://github.com/stoatchat/stoatchat/security/advisories/GHSA-6877-g673-f5r8

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