# CVE-2026-42538: DFIR-IRIS IRIS unrestricted file upload and stored XSS

Source: https://junglewise.ai/threats/cve-2026-42538-dfir-iris-iris-unrestricted-file-upload-and-stored-xss  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-04. Updated: 2026-06-04  
License: CC BY 4.0 with a link back

CVE-2026-42538 · Severity: medium · CVSS 6.3 · Published 2026-06-04

IRIS is a collaborative web platform used by incident responders to share technical details during security investigations. A vulnerability in the platform's file upload system allows users to upload malicious files, such as fake login pages or scripts. This could be exploited to trick other responders into revealing their credentials or to execute unauthorized actions within their web browser, potentially compromising sensitive investigation data.

Technologies: [DFIR-IRIS Iris](https://junglewise.ai/threats/technologies/iris). Vendors: [DFIR-IRIS](https://junglewise.ai/threats/vendors/dfir-iris).

## Quick answers

**Is CVE-2026-42538 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-42538 being exploited in the wild.

**How severe is CVE-2026-42538?** Medium severity, with a CVSS score of 6.3, published 4 June 2026.

**Which products and versions are affected?** DFIR-IRIS Iris < 2.4.28.

**Is there a fix for CVE-2026-42538?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-42538 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-42538?** Check whether you run DFIR-IRIS Iris 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 the IRIS web application's datastore component. The application fails to properly validate file extensions and MIME types, allowing an authenticated attacker to upload arbitrary HTML files containing malicious JavaScript. When these files are viewed by other users, the server serves them with a 'text/html' Content-Type, leading to Stored Cross-Site Scripting (XSS). This can be leveraged to steal session cookies, perform actions on behalf of other users, or host phishing content on a trusted domain. The vulnerability is patched in version 2.4.28 by implementing stricter file type enforcement.

## Affected products

- DFIR-IRIS IRIS < 2.4.28

## Timeline

- 2026-01-22: other: Vulnerability discovered/tested by researchers
- 2026-05-28: advisory: GitHub Security Advisory published
- 2026-06-04: disclosed: CVE published to NVD

## References

- [https://github.com/dfir-iris/iris-web/security/advisories/GHSA-m624-7744-2mhf](https://github.com/dfir-iris/iris-web/security/advisories/GHSA-m624-7744-2mhf)

## Related threats

- [IRIS unauthorized comment enumeration via case access](https://junglewise.ai/threats/cve-2026-92605-iris-unauthorized-comment-enumeration-via-case-access)
- [DFIR-IRIS IRIS Web Stored XSS in datastore upload function](https://junglewise.ai/threats/cve-2026-18361-dfir-iris-iris-web-stored-xss-in-datastore-upload-function)
- [DFIR-IRIS IRIS Web insufficient session expiration in logout function](https://junglewise.ai/threats/cve-2026-16970-dfir-iris-iris-web-insufficient-session-expiration-in-logout)
- [DFIR-IRIS IRIS Web Stored XSS in assets function](https://junglewise.ai/threats/cve-2026-16969-dfir-iris-iris-web-stored-xss-in-assets-function)
- [DFIR-IRIS IRIS incorrect authorization in alert management](https://junglewise.ai/threats/cve-2026-42547-dfir-iris-iris-incorrect-authorization-in-alert-management)