CVE-2026-100674

Medium

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.

SeverityMedium

CVSS4.3

Exploit probability—

ProductStoatchat

PublishedSep 26, 2026

First seenSep 26, 2026

Weakness typeCWE-180CWE-180

How to fix

Update

stoatchat stoatchat0.15.5 or later

Vendor advisories

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

Affected products

Product	Affected versions	Fixed in
stoatchat stoatchat	v < 0.15.5	0.15.5

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