Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-8474

MEDIUM · 5.3 CVSS v3.1 Published 2026-06-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability was discovered on Stormshield Network Security  * 4.3.0 to 4.3.41,  * 4.8.0 to 4.8.15,  * 5.0.0 to 5.0.5 It is possible to execute a reflected XSS attack on the login API available on Stormshield SNS appliance by executing a script on the victim's machine. The risks include the theft of cookies or other sensitive data, as well as the modification of page behavior, for example, by redirecting the victim to malicious websites.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A reflected XSS vulnerability exists in the login API of Stormshield SNS appliances across versions 4.3.0-4.3.41, 4.8.0-4.8.15, and 5.0.0-5.0.5. Attackers can inject malicious scripts that execute in victims' browsers, enabling cookie theft, sensitive data exfiltration, and page behavior modification including redirect attacks.

MitigationApply vendor-supplied patches or upgrade to a patched Stormshield SNS version beyond 5.0.5. Validate the login API response encoding and implement Content Security Policy headers as a defense-in-depth measure.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm Stormshield SNS is installed
    Identify whether Stormshield SNS appliance software is running in your environment. This may be visible in network scans, device inventory, or system documentation.
    Affected if Stormshield SNS software is present in your environment
  2. Determine the installed SNS version
    Access the appliance administrative interface or use the CLI command 'nsml show version' or check the system information page in the web management console to retrieve the exact version number.
    Affected if The installed version falls within 4.3.0-4.3.41, 4.8.0-4.8.15, or 5.0.0-5.0.5
  3. Verify the login API endpoint is accessible
    Check if the login API endpoint is exposed externally or internally by attempting to access the login page URL (typically /cgi-bin/nxadm.cgi or /auth/login) on the appliance. Review firewall or proxy logs for access attempts to these paths.
    Affected if The login API endpoint is reachable from any network where potential attackers could send malicious requests
  4. Inspect login request parameters for sanitization
    If you have access to logs or can test safely, examine whether the login API properly encodes or sanitizes input parameters. Submit a test XSS payload in the username or other login fields and check if it is reflected unescaped in the response.
    Affected if Login input parameters are reflected in responses without HTML encoding or sanitization

Your environment is affected if Stormshield SNS is running and the installed version falls within 4.3.0-4.3.41, 4.8.0-4.8.15, or 5.0.0-5.0.5, and the login API endpoint is accessible to potential attackers.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor-supplied patches or upgrade to a patched Stormshield SNS version beyond 5.0.5. Validate the login API response encoding and implement Content Security Policy headers as a defense-in-depth measure.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-8474 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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