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Traefik Client Plugin's Path Traversal Vulnerability Allows Arbitrary File Overwrite and Remote Code Execution

High severity GitHub Reviewed Published Aug 1, 2025 in traefik/traefik • Updated Aug 1, 2025

Package

gomod github.com/traefik/traefik/v2 (Go)

Affected versions

<= 2.11.27

Patched versions

2.11.28
gomod github.com/traefik/traefik/v3 (Go)
<= 3.4.4
>= 3.5.0-rc1, <= 3.5.0-rc2
3.4.5
3.5.0

Description

Summary

A path traversal vulnerability was discovered in WASM Traefik’s plugin installation mechanism. By supplying a maliciously crafted ZIP archive containing file paths with ../ sequences, an attacker can overwrite arbitrary files on the system outside of the intended plugin directory. This can lead to remote code execution (RCE), privilege escalation, persistence, or denial of service.
✅ After investigation, it is confirmed that no plugins on the Catalog were affected. There is no known impact.

Details

The vulnerability resides in the WASM plugin extraction logic, specifically in the unzipFile function (/plugins/client.go). The application constructs file paths during ZIP extraction using filepath.Join(destDir, f.Name) without validating or sanitizing f.Name. If the ZIP archive contains entries with ../, the resulting path can escape the intended directory, allowing writes to arbitrary locations on the host filesystem.

Attack Requirements

There are several requirements needed to make this attack possible:

  • The Traefik server should be deployed with plugins enabled with a WASM plugin (yaegi plugins are not impacted).
  • The attacker should have write access to a remote plugin asset loaded by the Traefik server
  • The attacker should craft a malicious version of this plugin

Warning

As clearly stated in the documentation, plugins are experimental in Traefik, and unsafe plugins could damage your infrastructure:

Experimental Features
Plugins can change the behavior of Traefik in unforeseen ways. Exercise caution when adding new plugins to production Traefik instances.

Impact

This vulnerability did not affect any plugin from the catalog. There is no known impact.
Additionally, the catalog will also prevent any compromised plugin to be available across all Traefik versions.
This vulnerability could allow an attacker to perform arbitrary file write outside the intended plugin extraction directory by crafting a malicious ZIP archive that includes ../ (directory traversal) in file paths.

References

@emilevauge emilevauge published to traefik/traefik Aug 1, 2025
Published to the GitHub Advisory Database Aug 1, 2025
Reviewed Aug 1, 2025
Last updated Aug 1, 2025

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity High
Attack Requirements Present
Privileges Required High
User interaction Passive
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability High
Subsequent System Impact Metrics
Confidentiality Low
Integrity Low
Availability Low

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L

EPSS score

Weaknesses

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Learn more on MITRE.

Path Traversal: 'dir..filename'

The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize 'dir..filename' (leading backslash dot dot) sequences that can resolve to a location that is outside of that directory. Learn more on MITRE.

CVE ID

CVE-2025-54386

GHSA ID

GHSA-q6gg-9f92-r9wg

Source code

Credits

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