XSS in Loft-Sh Loft

CVE-2026-42457

vCluster Platform provides a Kubernetes platform for managing virtual clusters, multi-tenancy, and cluster sharing. Prior to 4.4.3, 4.5.5, 4.6.2, 4.7.1, and 4.8.0, there is a Stored XSS attack vulnerability via the name field of a templateRef. This can lead to the execution of arbitrary external scripts within the platform's browser context. In the worst case, a malicious user could potentially create a new Global-Admin user, bypassing other security restrictions. The attacker needs the ability to create namespaces. This vulnerability is fixed in 4.4.3, 4.5.5, 4.6.2, 4.7.1, and 4.8.0.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.005 (43.2th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 43.2% 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-2026-42457: held from 0.003 to 0.005.

EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002

Affected products

  • Loft-Sh Loft — versions < 4.4.3, >=4.5.0-alpha.0 , < 4.5.5, >= 4.6.0-alpha.1, < 4.6.2

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-42457?
CVE-2026-42457 is a critical-severity vulnerability in Loft-Sh Loft, classified under Cross-site Scripting. CVSS score: 9.0/10. Published 2026-05-14.
How severe is CVE-2026-42457?
Critical severity. CVSS v3 base score is 9.0 out of 10.