CVE-2026-25126

PolarLearn's unvalidated vote direction allows vote count manipulation

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

polarnl · PolarLearn

CVSS v3.1 GITHUB

7.1 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N

EPSS

0.38% chance of exploitation in the next 30 days, 31st percentile

Published

2026-01-29

Updated

2026-02-02

Proof-of-concept exploits (1)

• Jvr2022/CVE-2026-251261★ · 2026-01-31

Security advisories

• polarnl/PolarLearn/security/advisories/GHSA-ghpx-5w2p-p3qp
• polarnl/PolarLearn/commit/e6227d94d0e53e854f6a46480db8cd1051184d41

References

• CVE Record
• NVD entry

Related

• CVE-2026-23745
• CVE-2026-29786
• CVE-2026-40345
• CVE-2026-46420