What’s Vulnerable › Vulnerabilities

CVE-2026-25885: PolarLearn allows Unauthenticated WebSocket access allows subscribing to and posting in arbitrary group chats

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-02-09 · updated 2026-06-17
• Weakness: CWE-285

Description

PolarLearn is a free and open-source learning program. In 0-PRERELEASE-16 and earlier, the group chat WebSocket at wss://polarlearn.nl/api/v1/ws can be used without logging in. An unauthenticated client can subscribe to any group chat by providing a group UUID, and can also send messages to any group. The server accepts the message and stores it in the group’s chatContent, so this is not just a visual spam issue.

Affected products

• polarnl PolarLearn: all versions

References

• https://github.com/polarnl/PolarLearn/commit/3ba588fda0d3f8e238483a20772719f27e52e79f
• https://github.com/polarnl/PolarLearn/security/advisories/GHSA-gvjm-5pw7-6c8c

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