CVE-2026-100674

Published: Sep 26, 2026Modified: Sep 30, 2026Deferred

5.3

Vector

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XShow less

Source: disclosure@vulncheck.com (Secondary)

Description

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.

Related CWEs

CWE-180

Incorrect Behavior Order: Validate Before Canonicalize

The product validates input before it is canonicalized, which prevents the product from detecting data that becomes invalid after the canonicalization step.

References (2)

https://github.com/stoatchat/stoatchat/security/advisories/GHSA-qcwh-c934-wrv5

Source: disclosure@vulncheck.com

https://www.vulncheck.com/advisories/stoatchat-before-0.15.5-username-validation-bypass-via-unicode-sanitization

Source: disclosure@vulncheck.com

Timeline

No history available yet.