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

> Attackers can manipulate vote counts by sending invalid direction values, bypassing intended business logic in PolarLearn.

- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Jan 2026
- **Updated:** 2 Feb 2026
- **Also known as:** GHSA-ghpx-5w2p-p3qp

## What is CVE-2026-25126?

CVE-2026-25126 is a high-severity vulnerability in polarnl PolarLearn, published on 29 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-25126?

It affects 1 product.


Products: Polarlearn Polarlearn.

## How do I fix CVE-2026-25126?

No fix has been published for CVE-2026-25126 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-25126 being exploited?

There is no known exploitation of CVE-2026-25126 in the wild and no public exploit code.

Public exploit code:

- CVE-2026-25126 Proof-of-Concept demonstrating vote count manipulation in PolarLearn due to improper runtime validation of the forum vote direction parameter. Published after upstream patch release. (github_poc): https://github.com/Jvr2022/CVE-2026-25126

## Other vulnerabilities in polarnl PolarLearn

- [CVE-2026-25885](https://insights.sbomify.com/CVE-2026-25885/): PolarLearn allows Unauthenticated WebSocket access allows subscribing to and posting in arbitrary group chats (critical 10.0)
- [CVE-2026-39322](https://insights.sbomify.com/CVE-2026-39322/): PolarLearn: Any password authenticates banned accounts and grants API access (critical 9.2)
- [CVE-2026-35610](https://insights.sbomify.com/CVE-2026-35610/): PolarLearn has a Server Action Admin Bypass in Account Management Actions (high 8.8)
- [CVE-2026-25222](https://insights.sbomify.com/CVE-2026-25222/): PolarLearn Affected by User Enumeration via Argon2 Timing Attack on Sign-In Endpoint (medium 6.3)
- [CVE-2026-25221](https://insights.sbomify.com/CVE-2026-25221/): PolarLearn has Multiple Login CSRFs via Missing OAuth state Parameter (GitHub & Google) (low 2.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-25126 and fix it if it is affected.

What it is: CVE-2026-25126 is a high-severity vulnerability in polarnl PolarLearn, published on 29 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-25126 in the wild and no public exploit code.

Affected product: polarnl PolarLearn. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-25126/ (Markdown: https://insights.sbomify.com/CVE-2026-25126/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-25126
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25126
- OSV: https://osv.dev/vulnerability/CVE-2026-25126

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-25126/
Summaries are generated and may contain mistakes; the official description above is the record.