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.

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
stoatchat stoatchat unaffected
Version Status Constraints
0 affected < 0.15.5
0.15.5 unaffected —

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No data.

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Project Subscriptions

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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/stoatchat/stoatchat/security/advisories/GHSA-qcwh-c934-wrv5 cve-icon cve-icon
https://www.vulncheck.com/advisories/stoatchat-before-0.15.5-username-validation-bypass-via-unicode-sanitization cve-icon cve-icon
History

Sat, 26 Sep 2026 13:30:00 +0000

Type Values Removed Values Added
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.
Title stoatchat before 0.15.5 Username Validation Bypass via Unicode Sanitization
Weaknesses CWE-180
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N'}

cvssV4_0

{'score': 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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-26T13:23:37.620Z

Reserved: 2026-09-26T02:34:55.635Z

Link: CVE-2026-100674

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-26T14:16:51.297

Modified: 2026-09-26T14:16:51.297

Link: CVE-2026-100674

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-26T15:45:14Z

Weaknesses