Browser script execution via reflected 404 content
Published Jun 30, 2026 · Updated Jun 30, 2026
Reflected XSS in StoneFly Storage Concentrator and SCVM before 8.0.4.22 allows remote attackers to execute script via a crafted URL. The 404 error handler echoes unsanitized URL content into its error page, causing the browser to interpret attacker-supplied markup as script. Exploitation requires an authenticated user to visit the malicious URL and exposes that browser session to cookie theft, redirects, and unauthorized actions.
Summary
What happened
Reflected XSS in StoneFly Storage Concentrator and SCVM before 8.0.4.22 allows remote attackers to execute script via a crafted URL. The 404 error handler echoes unsanitized URL content into its error page, causing the browser to interpret attacker-supplied markup as script. Exploitation requires an authenticated user to visit the malicious URL and exposes that browser session to cookie theft, redirects, and unauthorized actions.
The record
- CVE
- CVE-2026-50040
- Published
- Jun 30, 2026
- Updated
- Jun 30, 2026
- Vendor
- StoneFly, Inc.
- Product
- Storage Concentrator
- Classifications
- CWE-79, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 30, 2026CVE publishedPublication date reported by the CVE source.
- Jun 30, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0 <8.0.4.22
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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