CVE-2025-53829 ownCloud 10 Path Traversal Arbitrary Code Execution Vulnerability

Technical summary

CVE-2025-53829 is a path traversal vulnerability (CWE-23) in ownCloud 10 that permits authenticated administrative users to traverse the file system beyond intended boundaries and achieve remote code execution. The vulnerability requires high privilege level (PR:H) and non-interactive exploitation, suggesting it may be triggered through administrative interfaces or automation workflows. The CVSS 3.1 score of 8.0 reflects the high impact across confidentiality, integrity, and availability when successfully exploited, with a network-accessible attack surface (AV:N). The vulnerability does not require user interaction and can affect the entire system scope.

Business impact

Organizations deploying ownCloud 10 for file synchronization and sharing face credential compromise risk, particularly when administrative accounts are shared, delegated, or exposed through other means. Exploitation could lead to unauthorized data exfiltration, modification of shared files affecting downstream users, and potential lateral movement into connected infrastructure. For enterprises relying on ownCloud for document collaboration, this creates both data loss and business continuity exposure. The requirement for administrative privileges narrows the immediate blast radius but elevates risk in environments with weak administrative access controls or shared admin accounts.

Affected systems

ownCloud 10 versions prior to 10.15.3 are affected. The vendor has not disclosed specific version ranges beyond this, but organizations running any ownCloud 10 release should verify their exact version against the 10.15.3 threshold. This affects self-hosted ownCloud deployments; cloud-hosted instances managed by Nextcloud or official providers may receive patches through different mechanisms and timelines.

Exploitability

Exploitation requires valid administrative credentials and network access to the ownCloud instance. The CVSS vector indicates moderate attack complexity (AC:H), suggesting some additional prerequisites or conditions must be met beyond simply possessing admin credentials—possibly specific application states, configuration choices, or multi-step interaction patterns. No public exploit code or active exploitation in the wild has been documented (KEV status: not included). The barrier to exploitation is meaningful but not insurmountable for threat actors who have compromised or been granted admin access.

Remediation

Upgrade ownCloud 10 to version 10.15.3 or later immediately. Verify the exact version installed before upgrading by checking the ownCloud admin dashboard or filesystem. Test patches in a non-production environment first if possible. Additionally, audit administrative account access logs to detect any suspicious activity, reduce the number of accounts with admin privileges, and implement multi-factor authentication for administrative access to limit credential-based attack surface.

Patch guidance

Vendor guidance is to upgrade ownCloud 10 to version 10.15.3 or later. Follow the official ownCloud upgrade documentation for your deployment model (Docker, package manager, manual). Before applying the patch, back up your ownCloud database and configuration files. Verify patch installation by checking the version string in the admin panel or via command line. If running versions older than ownCloud 10, verify that they are not affected by consulting the official security advisory.

Detection guidance

Monitor ownCloud access logs for administrative accounts performing unusual file operations or commands, particularly those traversing unexpected directory paths or executing system commands through the application interface. Look for audit trail gaps or disabled logging, which may indicate tampering. Endpoint detection and response (EDR) tools should flag unexpected process execution spawned from the PHP-FPM or Apache process running ownCloud. Network intrusion detection systems may flag suspicious URL patterns containing path traversal sequences (../ or encoded variants) in requests to ownCloud administrative endpoints.

Why prioritize this

This vulnerability merits high priority due to its broad system impact (CVSS 8.0), complete compromise potential (confidentiality, integrity, and availability all affected), and network accessibility. While the administrative privilege requirement limits the immediate threat surface, the insider-threat vector and ease of chaining this with credential compromise exploits (e.g., phishing, password reuse) make it a realistic attack path for determined adversaries. Organizations with weak administrative access controls or shared admin credentials should treat this as critical.

Risk score, explained

The CVSS 3.1 score of 8.0 (HIGH) reflects a high-impact vulnerability with meaningful but not insurmountable barriers to exploitation. The network attack vector (AV:N) and high privileges requirement (PR:H) balance each other; the moderate attack complexity (AC:H) and high impact across all three security properties (C:H, I:H, A:H) drive the substantial score. The changed scope (S:C) indicates that exploitation can affect resources beyond the vulnerable component itself, elevating risk in connected system environments.

Frequently asked questions