Vulnerability in Stoatchat
CVE-2026-100674
stoatchat before 0.15.5 fails to revalidate usernames after Unicode sanitization, allowing attackers to create usernames with forbidden characters by submitting Unicode letters that transform into rejected characters. Attackers can bypass character allowlists and length limits to create reserved-name lookalikes, embed special characters, and exceed the 32-character storage limit.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (14.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 14th percentile — 14.5% 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: 0.002 · change: 0.000
Affected products
Weakness classification (CWE)
References
- GitHub Security Advisory (GHSA-qcwh-c934-wrv5) (vendor-advisory)
- VulnCheck Advisory: stoatchat before 0.15.5 Username Validation Bypass via Unicode Sanitization (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100674?
- CVE-2026-100674 is a medium-severity vulnerability in Stoatchat, classified under CWE-180. CVSS score: 4.3/10. Published 2026-09-26.
- How severe is CVE-2026-100674?
- Medium severity. CVSS v3 base score is 4.3 out of 10.