CVE-2025-54593 in FreshRSS
Summary
by MITRE • 08/01/2025
FreshRSS is a free, self-hostable RSS aggregator. In versions 1.26.1 and below, an authenticated administrator user can execute arbitrary code on the FreshRSS server by modifying the update URL to one they control, and gain code execution after running an update. After successfully executing code, user data including hashed passwords can be exfiltrated, the instance can be defaced when file permissions allow. Malicious code can be inserted into the instance to steal plaintext passwords, among others. This is fixed in version 1.26.2.
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Analysis
by VulDB Data Team • 08/05/2025
FreshRSS represents a significant security vulnerability through CVE-2025-54593 which affects versions 1.26.1 and earlier, creating a critical path for authenticated administrators to achieve arbitrary code execution on the server. This vulnerability stems from insufficient input validation when processing update URLs, allowing an attacker with administrative privileges to manipulate the update mechanism and inject malicious code that executes with the privileges of the FreshRSS service account. The flaw specifically manifests when administrators attempt to update the RSS aggregator, providing an opportunity for code injection through the update URL parameter that lacks proper sanitization or validation checks.
The technical implementation of this vulnerability aligns with CWE-94, which describes inadequate validation of a control flow modification, and represents a direct exploitation of the update mechanism within the application's administrative interface. Attackers can leverage this by crafting a malicious update URL pointing to their controlled server, where they host code that executes upon the update process. The vulnerability essentially creates a code execution vector that bypasses normal access controls, as the administrative user's privileges are leveraged to execute the malicious payload without additional authentication requirements. The exploitation process is straightforward and requires only administrative access to the FreshRSS instance, making it particularly dangerous for environments where administrative credentials might be compromised or where privilege escalation occurs through other means.
The operational impact of this vulnerability extends beyond simple code execution, as successful exploitation enables attackers to access sensitive user data including hashed passwords stored within the FreshRSS database. The compromised instance becomes a potential staging ground for further attacks, with the ability to deface the web interface when file permissions permit, and to inject additional malicious code that could harvest plaintext passwords from users. This represents a complete compromise of the service's integrity and confidentiality, as attackers can persist within the environment and potentially escalate their access to other systems if the FreshRSS server has network access to additional resources. The vulnerability's severity is amplified by its requirement for only administrative privileges, which are often more accessible than system-level credentials and frequently maintained with less stringent security controls.
Organizations utilizing FreshRSS should immediately implement mitigation strategies including the mandatory upgrade to version 1.26.2, which addresses the vulnerability through proper input validation and sanitization of update URL parameters. Additional protective measures include implementing strict administrative access controls with multi-factor authentication, monitoring update activities within the application logs, and establishing network segmentation to limit the potential impact of a successful compromise. The vulnerability demonstrates the importance of validating all user-supplied input within administrative functions, particularly those that involve system-level operations such as updates, and aligns with ATT&CK technique T1059 for executing malicious code and T1566 for credential access through various means including password harvesting. Security teams should also consider implementing automated patch management processes to ensure rapid deployment of security updates and prevent similar vulnerabilities from persisting in the environment.