EUVD-2026-19853Severity by source
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
3DescriptionGitHub Advisory
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.
AnalysisAI
Authentication bypass in PolarLearn ≤0-PRERELEASE-15 allows unauthenticated remote attackers to gain authenticated session access as banned users without password verification. The flaw enables complete account takeover and unauthorized data access through a session generation vulnerability in the /api/v1/auth/sign-in endpoint. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | PolarLearn versions 0-PRERELEASE-15 and earlier. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | This represents an elevated real-world risk despite pre-release software status. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker identifies a banned user account through publicly visible forum posts or user enumeration on the PolarLearn platform. The attacker sends a crafted POST request to /api/v1/auth/sign-in with the banned user's username and any arbitrary password value. … |
| Remediation | Upgrade immediately to PolarLearn version 0-PRERELEASE-16 or later, which addresses the authentication sequence vulnerability by enforcing password verification before session creation. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Identify all PolarLearn deployments and their current versions; isolate systems running version 0-PRERELEASE-15 or earlier from untrusted networks if possible. …
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External POC / Exploit Code
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