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stoatchat before 0.15.5 Username Validation Bypass via Unicode Sanitization

Priority LOW 24CWE-180Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · Low · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00234 14th percentileScored 2026-11-07
Fix Fixed stoatchat (stoatchat): 0.15.5

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
stoatchatstoatchatbefore 0.15.50.15.5Patch availableCNA
  • stoatchat Vendorstoatchat Affected before 0.15.5 Fixed in 0.15.5 Patch available CNA

Remediation

  • Fix · CNA stoatchat (stoatchat) Fixed in 0.15.5

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    stoatchat 0.15.5

    6 records Highest priority Priority HIGH 4 HIGH, 1 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-64832 stoatchat before 0.15.5 Local Filesystem Read via SVGPriority HIGH 77
    • TI-2026-64833 stoatchat before 0.15.5 Account Enumeration via Error LocationPriority HIGH 70
    • TI-2026-64834 stoatchat before 0.15.5 MFA Brute Force via Insufficient Rate LimitingPriority HIGH 69

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-100674
  2. 2026-10-03 Alias added: GHSA-j26j-r3xm-q4wf

References

  • TI-2026-45152 stoatchat before 0.13.5 Unauthenticated SSRF via proxy and embed endpoints CVSS 4.0CRITICAL 9.2
  • TI-2026-64832 stoatchat before 0.15.5 Local Filesystem Read via SVG CVSS 4.0HIGH 8.8
  • TI-2026-51266 stoatchat before 0.15.0 Uncapped SVG Rendering Denial of Service CVSS 4.0HIGH 8.7
  • TI-2026-45038 stoatchat < 0.14.0 SSRF via DNS-based IP Blocklist Bypass CVSS 4.0HIGH 7.7
  • TI-2026-64833 stoatchat before 0.15.5 Account Enumeration via Error Location CVSS 4.0MEDIUM 6.9
  • TI-2026-51267 stoatchat before 0.15.0 SSRF via IPv6 unspecified address bypass CVSS 4.0MEDIUM 6.9
See all 15 →

Sources