CVE-2026-100674CWE-180

CVE-2026-100674

Medium · published September 26, 2026

CVSS v3.1
4.3
EPSS
0%
Percentile
13.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
4.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
CVSS v4.0
5.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
EPSS
0.00234 · 13.5th percentile
Weakness
CWE-180 · Incorrect Behavior Order: Validate Before Canonicalize
Published
2026-09-26T18:16Z
References (2)
https://github.com/stoatchat/stoatchat/security/advisories/GHSA-qcwh-c934-wrv5 · [email protected]https://www.vulncheck.com/advisories/stoatchat-before-0.15.5-username-validation-bypass-via-unicode-sanitization · [email protected]
EPSS history
Timeline
  • 28 SEP 03:25Z
    EPSS moved — → 0%
    epss
  • 26 SEP 13:23Z
    stoatchat before 0.15.5 Username Validation Bypass via Unicode Sanitization
    cvelistv5