Vulnerability in Stoatchat
CVE-2026-100678
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (22.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 22.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
Weakness classification (CWE)
References
- GitHub Security Advisory (GHSA-6877-g673-f5r8) (vendor-advisory)
- VulnCheck Advisory: stoatchat before 0.15.5 MFA Brute Force via Insufficient Rate Limiting (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100678?
- CVE-2026-100678 is a medium-severity vulnerability in Stoatchat, classified under Improper Restriction of Excessive Authentication Attempts. CVSS score: 6.5/10. Published 2026-09-26.
- How severe is CVE-2026-100678?
- Medium severity. CVSS v3 base score is 6.5 out of 10.