CVE-2026-25885

PolarLearn allows Unauthenticated WebSocket access allows subscribing to and posting in arbitrary group chats

Published Feb 9, 2026 CVSS 4.0 · 10 Critical EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Polarlearn
Polarlearn polarlearn
CPEs cpe:2.3:a:polarlearn:polarlearn:-:*:*:*:*:*:*:*
Vendors & Products Polarlearn
Polarlearn polarlearn
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Polarnl
Polarnl polarlearn
Vendors & Products Polarnl
Polarnl polarlearn
Type Values Removed Values Added
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.
Title PolarLearn allows Unauthenticated WebSocket access allows subscribing to and posting in arbitrary group chats
Weaknesses CWE-285
CWE-306
References
Metrics cvssV4_0

{'score': 10, '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Feb 10, 2026, 3:58 PM
Reserved
Feb 6, 2026, 9:08 PM
Status
Analyzed
Published
Feb 9, 2026, 10:16 PM
Modified
Jun 17, 2026, 10:25 AM