CVE-2026-42457

vCluster Platform: Stored XSS can lead to privilege escalation

State: Published
Severity: 9.0 Critical
Published: May 14, 2026
Updated: May 14, 2026
Reserved: Apr 27, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	9.0 Critical	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H	GitHub_M

Weaknesses

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Affected Products

Product	Versions
loftloft-sh	< 4.4.3Affected >=4.5.0-alpha.0 , < 4.5.5Affected >= 4.6.0-alpha.1, < 4.6.2Affected >= 4.7.0-alpha.0, < 4.7.1Affected

References

https://github.com/loft-sh/loft/security/advisories/GHSA-x7cq-v3h6-426c

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