Unauthenticated chat disclosure and injection via unchecked WebSocket
Published Feb 9, 2026 · Updated Feb 9, 2026
Improper authorization in PolarLearn 0-PRERELEASE-16 and earlier allows remote attackers to read and write group chats via WebSocket. The onMessage handler in src/hono-server.ts accepts client-supplied group identifiers for subscribe and chat events without authentication or membership checks. Knowledge or guessing of a group UUID is sufficient to receive private chat traffic and persist arbitrary messages in that group's chatContent.
Summary
What happened
Improper authorization in PolarLearn 0-PRERELEASE-16 and earlier allows remote attackers to read and write group chats via WebSocket. The onMessage handler in src/hono-server.ts accepts client-supplied group identifiers for subscribe and chat events without authentication or membership checks. Knowledge or guessing of a group UUID is sufficient to receive private chat traffic and persist arbitrary messages in that group's chatContent.
The record
- CVE
- CVE-2026-25885
- Published
- Feb 9, 2026
- Updated
- Feb 9, 2026
- Vendor
- PolarNL
- Product
- PolarLearn
- Classifications
- CWE-285, CWE-306, T1565.001, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 9, 2026CVE publishedPublication date reported by the CVE source.
- Feb 9, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 0-PRERELEASE-16
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
- Unauthenticated WebSocket group-chat PoCproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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