# CVE-2026-63228: Three Learning Koollab LMS unrestricted image upload in feedback endpoint

Source: https://junglewise.ai/threats/cve-2026-63228-three-learning-koollab-lms-unrestricted-image-upload-in-feedback  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-29. Updated: 2026-07-29  
License: CC BY 4.0 with a link back

CVE-2026-63228 · Severity: low · CVSS 2.6 · Published 2026-07-29

Koollab LMS, a cloud-based learning management system, contains a vulnerability that allows users to upload malicious files disguised as images. An attacker with a valid account could use the feedback registration feature to upload harmful content to the server. While the immediate impact is limited, this could be used as a stepping stone for more complex attacks against the platform's infrastructure.

Technologies: [Three Learning Koollab LMS](https://junglewise.ai/threats/technologies/koollab-lms). Vendors: [Three Learning](https://junglewise.ai/threats/vendors/three-learning).

## Quick answers

**Is CVE-2026-63228 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-63228 being exploited in the wild.

**How severe is CVE-2026-63228?** Low severity, with a CVSS score of 2.6, published 29 July 2026.

**Which products and versions are affected?** Three Learning Koollab LMS 5.3.2.

**Is there a fix for CVE-2026-63228?** A patch was published on 2026-04-26: Vendor patched cloud instances Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-63228 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-63228?** Check whether you run Three Learning Koollab LMS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An unrestricted file upload vulnerability exists in Koollab LMS version 5.3.2 within the feedback mail registration endpoint. The application fails to properly validate the contents of uploaded files, allowing an authenticated attacker to bypass extension-based filters by disguising malicious payloads as image files. While the CVSS score is low due to high attack complexity and required user interaction, successful exploitation allows an attacker to place arbitrary content on the server, which could facilitate secondary attacks. The vendor, Three Learning, has patched this vulnerability across all cloud-hosted SaaS instances.

## Affected products

- Three Learning Koollab LMS 5.3.2

## Timeline

- 2026-04-14: disclosed: Vendor disclosure
- 2026-04-26: patched: Vendor patched cloud instances
- 2026-07-29: advisory: Public release of advisory

## References

- [https://www.csa.gov.sg/alerts-and-advisories/alerts/al-2026-094/](https://www.csa.gov.sg/alerts-and-advisories/alerts/al-2026-094/)

## Related threats

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- [Three Learning Koollab LMS information disclosure in course status endpoint](https://junglewise.ai/threats/cve-2026-63240-three-learning-koollab-lms-information-disclosure-in-course)
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- [Three Learning Koollab LMS authentication bypass in 2FA endpoint](https://junglewise.ai/threats/cve-2026-63238-three-learning-koollab-lms-authentication-bypass-in-2fa-endpoint)