# CVE-2026-8474: Stormshield Network Security reflected XSS in login API

Source: https://junglewise.ai/threats/cve-2026-8474-stormshield-network-security-reflected-xss-in-login-api  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-01. Updated: 2026-06-01  
License: CC BY 4.0 with a link back

CVE-2026-8474 · Severity: medium · CVSS 5.3 · Published 2026-06-01

Stormshield Network Security (SNS) is a firewall and security appliance used to protect corporate networks. A vulnerability in its login interface could allow an attacker to execute malicious scripts in a user's browser. This could lead to the theft of login session cookies, unauthorized access to the management console, or the redirection of administrators to fraudulent websites.

Technologies: [Stormshield Network Security](https://junglewise.ai/threats/technologies/network-security). Vendors: [Stormshield](https://junglewise.ai/threats/vendors/stormshield).

## Quick answers

**Is CVE-2026-8474 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-8474 being exploited in the wild.

**How severe is CVE-2026-8474?** Medium severity, with a CVSS score of 5.3, published 1 June 2026.

**Which products and versions are affected?** Stormshield Network Security 4.3.0 to 4.3.41, 4.8.0 to 4.8.15, 5.0.0 to 5.0.5.

**Is there a fix for CVE-2026-8474?** 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-2026-8474 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-8474?** Check whether you run Stormshield Network Security 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

A reflected cross-site scripting (XSS) vulnerability exists in the login API of Stormshield Network Security (SNS) appliances. The flaw is caused by improper neutralization of user-supplied input during web page generation (CWE-79). An unauthenticated remote attacker can exploit this by tricking a user into clicking a specially crafted link or visiting a malicious site that interacts with the SNS login API. Successful exploitation allows the attacker to execute arbitrary JavaScript in the context of the victim's browser session, potentially leading to session hijacking via cookie theft or unauthorized modification of the page's behavior. The vulnerability is fixed in versions 4.3.42, 4.8.16, and 5.0.6.

## Affected products

- Stormshield Stormshield Network Security (SNS) 4.3.0 to 4.3.41, 4.8.0 to 4.8.15, 5.0.0 to 5.0.5

## Timeline

- 2026-01-13: other: Vulnerability discovered
- 2026-02-19: other: Initial internal advisory release (v1)
- 2026-05-21: advisory: Public advisory published by Stormshield (v2)
- 2026-06-01: disclosed: CVE published to NVD

## References

- [https://advisories.stormshield.eu/2026-003/](https://advisories.stormshield.eu/2026-003/)

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