CVE-2026-25885 CRITICAL

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

Vendor Polarnl
Product PolarLearn
Weakness CWE-285
Published February 9, 2026
Last update February 10, 2026
View on NVD All CVEs

CVSS base score

10.0/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

February 9, 2026 CVE published
February 10, 2026 Record updated