What’s Vulnerable › Vulnerabilities

CVE-2026-25126: PolarLearn's unvalidated vote direction allows vote count manipulation

• Severity: high (CVSS 7.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-01-29 · updated 2026-06-17
• Weakness: CWE-20

Description

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.

Affected products

• polarnl PolarLearn: all versions

References

• https://github.com/polarnl/PolarLearn/commit/e6227d94d0e53e854f6a46480db8cd1051184d41
• https://github.com/polarnl/PolarLearn/security/advisories/GHSA-ghpx-5w2p-p3qp

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