CVE-2026-25222 MEDIUM

CVE-2026-25222: PolarLearn Affected by User Enumeration via Argon2 Timing Attack on Sign-In Endpoint

Vendor Polarnl
Product PolarLearn
Weakness CWE-200 · Info exposure
Published February 2, 2026
Last update February 4, 2026

CVSS base score

6.3/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N

What the vulnerability does

01Description

PolarLearn is a free and open-source learning program. In 0-PRERELEASE-15 and earlier, a timing attack vulnerability in the sign-in process allows unauthenticated attackers to determine if a specific email address is registered on the platform. By measuring the response time of the login endpoint, an attacker can distinguish between valid and invalid email addresses. This occurs because the server only performs the computationally expensive Argon2 password hashing if the user exists in the database. Requests for existing users take significantly longer (~650ms) than requests for non-existent users (~160ms).

Key dates

02Disclosure timeline

February 2, 2026 CVE published
February 4, 2026 Record updated