---
cve: "CVE-2026-100678"
severity: "HIGH"
cvss: 8.3
epss: "0.2%"
vendor: "stoatchat"
kev: false
exploited: false
published: "2026-09-26 14:16:51"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-29T12:07:41+02:00"
---

# CVE-2026-100678

> 8.3 HIGH · 🧪 PoC

## Beschreibung

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.

## CNA-Record (Kanon, cvelistV5)

- CNA: **VulnCheck**
- State: PUBLISHED
- Stand: 2026-09-26 13:23:40
- CNA-CVSS: **8.3** (`CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N`)

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Hoch | good |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- dc31dd7e62c1f8806b663549700a4121537b9530 (Commit)

## Referenzen

- <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>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-100678) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_