Vulnerability · Published Feb 9, 2026 · Assigned by GitHub_M

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

Critical 10.0

In plain English

A critical-severity missing authentication in PolarLearn from polarnl. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities).

Severity (CVSS 4.0)10.0Critical

Exploit odds (30 days)0.3%top 72.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
polarnl	PolarLearn	< 0-PRERELEASE-16

Weakness: CWE-285, CWE-306 · 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

References

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