XSS in Stonefly Storage Concentrator

CVE-2026-50040

Storage Concentrator (SC & SCVM) is vulnerable to reflected cross-site scripting due to unsanitized content being echoed back in 404 error pages. An attacker can craft a malicious URL that, when visited by an authenticated user, causes arbitrary script content to execute within the victim's browser session in the context of the application. This could be leveraged to steal session cookies, redirect users, or perform unauthorized actions on behalf of the victim.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (23.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 23.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-50040: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-50040?
CVE-2026-50040 is a medium-severity vulnerability in Stonefly Storage Concentrator, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-06-30.
How severe is CVE-2026-50040?
Medium severity. CVSS v3 base score is 6.1 out of 10.