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GHSA-5v3h-x4wf-5c35

HighCVSS 8.4 / 10
Published May 7, 2026·Last modified May 7, 2026
Affected Components(0)

No affected components available

Description

Impact

A vulnerability has been identified in Rancher's Extensions where malicious code can be injected in Rancher through a path traversal in the compressedEndpoint field inside a UIPlugin deployment. A malicious UI extension could abuse that to:

  • Overwrite Rancher binaries or configuration to inject code.
  • Write to /var/lib/rancher/ to tamper with cluster state.
  • If hostPath volumes are mounted, write to the host node filesystem.
  • Use this issue to chain with other attack vectors.

By default only the administrator can deploy UI extensions, unless permissions are granted to other users. It's always recommended to only install extensions that come from sources trusted by the user.

Please consult the associated MITRE CAPEC-126 - Technique - Path Traversal for further information about this category of attack.

Patches

This vulnerability is addressed by ensuring that:

  • The file defined by the UI Plugin CR's compressedEndpoint has to be created inside the cache directory and cannot contain ../. If that is not possible, the installation will fail and the file won't be created.
  • The icons referenced by Cluster Repos' index.yaml file always resolves to a file inside the repository directory.

Patched versions of Rancher include releases v2.14.1, v2.13.5, v2.12.9, v2.11.13.

Workarounds

There is no workaround. The user must be careful about which UI Plugins they install.

Resources

If there are any questions or comments about this advisory:

Risk Scores
Base Score
8.4

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs high-level or administrative privileges. The attacker needs the user to perform some action, like clicking a link. The vulnerability can affect other systems as well, not just the initial system. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.

Threat Intelligence
7.7

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
0.37%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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High severity
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