TI-2026-20289 Aliases CVE-2026-25126

PolarLearn's unvalidated vote direction allows vote count manipulation

LOW 31CWE-20Published 2026-01-29 · Updated 2026-02-02

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: Low · High · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

PolarLearn is a free and open-source learning program. Prior to version 0-PRERELEASE-15, the vote API route (`POST /api/v1/forum/vote`) trusts the JSON body’s `direction` value without runtime validation. TypeScript types are not enforced at runtime, so an attacker can send arbitrary strings (e.g., `"x"`) as `direction`. Downstream (`VoteServer`) treats any non-`"up"` and non-`null` value as a downvote and persists the invalid value in `votes_data`. This can be exploited to bypass intended business logic. Version 0-PRERELEASE-15 fixes the vulnerability.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00376 31st percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed PolarLearn (polarnl): 0-PRERELEASE-15

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
polarnl	PolarLearn	before 0-PRERELEASE-15	0-PRERELEASE-15	Patch available	CNA

PolarLearn Vendorpolarnl Affected before 0-PRERELEASE-15 Fixed in 0-PRERELEASE-15 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:polarlearn:polarlearn:-:::::::*	not specified by NVD	Vulnerable	polarnl

cpe:2.3:a:polarlearn:polarlearn:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·polarnl

Remediation

Fix · CNA PolarLearn (polarnl) Fixed in 0-PRERELEASE-15

Timeline

2026-10-02 Threatist record created from CVE-2026-25126

References

Exploit 1

https://github.com/polarnl/PolarLearn/security/advisories/GHSA-ghpx-5w2p-p3qp

Patch 1

https://github.com/polarnl/PolarLearn/commit/e6227d94d0e53e854f6a46480db8cd1051184d41

TI-2026-27712 PolarLearn has a Server Action Admin Bypass in Account Management Actions CVSS 3.1HIGH 8.8
TI-2026-20372 PolarLearn Affected by User Enumeration via Argon2 Timing Attack on Sign-In Endpoint CVSS 4.0MEDIUM 6.3
TI-2026-20925 PolarLearn allows Unauthenticated WebSocket access allows subscribing to and posting in arbitrary group chats CVSS 4.0CRITICAL 10.0
TI-2026-20371 PolarLearn has Multiple Login CSRFs via Missing OAuth state Parameter (GitHub & Google) CVSS 4.0LOW 2.3
TI-2026-28311 PolarLearn: Any password authenticates banned accounts and grants API access CVSS 4.0CRITICAL 9.2

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences