Auth bypass in Polarlearn
CVE-2026-25885
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.
EPSS: 0.003 (20.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
Affected products
- Polarlearn
- Polarnl Polarlearn — versions < 0-PRERELEASE-16
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-25885?
- CVE-2026-25885 is a high-severity vulnerability in Polarlearn, classified under Improper Authorization. CVSS score: 7.5/10. Published 2026-02-09.
- How severe is CVE-2026-25885?
- High severity. CVSS v3 base score is 7.5 out of 10.