CVE-2026-25885: critical vulnerability in polarnl PolarLearn
PolarLearn allows Unauthenticated WebSocket access allows subscribing to and posting in arbitrary group chats
Published · Updated
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
28Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 10epss 0.3%
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.
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
Affected products
polarnl · PolarLearnRelated CVEs — polarnl PolarLearn
In the same product, most dangerous first.
CVE-2026-25222MEDIUMPolarLearn Affected by User Enumeration via Argon2 Timing Attack on Sign-In EndpointEPSS 0.5%CVE-2026-25126HIGHPolarLearn's unvalidated vote direction allows vote count manipulationEPSS 0.4%CVE-2026-35610HIGHPolarLearn has a Server Action Admin Bypass in Account Management ActionsEPSS 0.3%CVE-2026-39322CRITICALPolarLearn: Any password authenticates banned accounts and grants API accessEPSS 0.2%CVE-2026-25221LOWPolarLearn has Multiple Login CSRFs via Missing OAuth state Parameter (GitHub & Google)EPSS 0.2%