Auth bypass in Stoatchat
CVE-2026-100679
stoatchat before 0.15.5 fails to validate that MFA tickets belong to the authenticated user, allowing attackers to bypass MFA by using their own valid ticket with another user's session token. Attackers can obtain a ticket from their own account and use it with a victim's session token to disable TOTP, view recovery codes, or perform other sensitive operations without providing the victim's credentials.
Vulnerability class: IDOR (Insecure Direct Object Reference)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (35.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 35.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
Weakness classification (CWE)
References
- GitHub Security Advisory (GHSA-gwg6-q3c3-97cx) (vendor-advisory)
- VulnCheck Advisory: stoatchat before 0.15.5 MFA Bypass via Cross-Account Ticket (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100679?
- CVE-2026-100679 is a high-severity vulnerability in Stoatchat, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 8.8/10. Published 2026-09-26.
- How severe is CVE-2026-100679?
- High severity. CVSS v3 base score is 8.8 out of 10.