Account impersonation via permissive Unicode username validation
Published Dec 2, 2025 · Updated Dec 2, 2025
Username validation in Revive Adserver 6.0.3 and earlier allows remote authenticated users to impersonate existing accounts. The user-creation path rejected control characters and whitespace but accepted other UTF-8 input, including homoglyphs, zero-width spaces, and RTL overrides that render like legitimate names. User-creation permission is required; a crafted lookalike account can mislead an administrator into granting it the intended user's permissions.
Summary
What happened
Username validation in Revive Adserver 6.0.3 and earlier allows remote authenticated users to impersonate existing accounts. The user-creation path rejected control characters and whitespace but accepted other UTF-8 input, including homoglyphs, zero-width spaces, and RTL overrides that render like legitimate names. User-creation permission is required; a crafted lookalike account can mislead an administrator into granting it the intended user's permissions.
The record
- CVE
- CVE-2025-55129
- Published
- Dec 2, 2025
- Updated
- Dec 2, 2025
- Vendor
- Revive Adserver Project
- Product
- Revive Adserver
- Classifications
- CWE-184, CWE-176, T1036
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Dec 2, 2025CVE publishedPublication date reported by the CVE source.
- Dec 2, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=6 <=6.0.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- HackerOne username-impersonation proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo