CVE-2026-39322: PolarLearn: Any password authenticates banned accounts and grants API access

PolarLearn is a free and open-source learning program. In 0-PRERELEASE-15 and earlier, POST /api/v1/auth/sign-in creates a valid session for banned accounts before verifying the supplied password. That session is then accepted across authenticated /api routes, enabling account data access and authenticated actions as the banned user.