CVE-2025-3485: Alltena Allegra RCE Vulnerability

CVE-2025-3485 Overview

CVE-2025-3485 is a directory traversal vulnerability in Alltena Allegra that leads to remote code execution. The flaw resides in the extractFileFromZip method, which fails to validate user-supplied paths before performing file operations. Authenticated attackers can leverage this weakness to write files outside the intended extraction directory and execute arbitrary code in the context of the running process. The issue was reported through the Zero Day Initiative under identifier ZDI-CAN-26524 and disclosed as advisory ZDI-25-254. It is classified under CWE-22 (Improper Limitation of a Pathname to a Restricted Directory).

Critical Impact
Authenticated attackers can achieve remote code execution on Allegra installations by exploiting improper path validation in ZIP archive extraction.

Affected Products

Alltena Allegra versions prior to 8.1.2
CPE: cpe:2.3:a:alltena:allegra:*:*:*:*:*:*:*:*
Deployments exposing Allegra project management functionality to authenticated users

Discovery Timeline

2025-06-06 - CVE-2025-3485 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-3485

Vulnerability Analysis

Allegra is a project management and issue tracking platform developed by Alltena. The application processes ZIP archives through the extractFileFromZip method, which extracts files into directories on the server. The method accepts file path entries from within the archive and uses them directly in file system write operations.

Because the method does not normalize or validate the entries, an attacker can craft a ZIP archive containing entries with traversal sequences such as ../ in their paths. When Allegra processes the archive, the extraction routine resolves these sequences and writes attacker-controlled content outside the intended extraction directory. Writing a file to a location loaded by the application, such as a web-accessible directory or a scheduled task path, produces code execution in the context of the Allegra process.

The vulnerability requires authentication but no user interaction. Attack complexity is low, and the network attack vector allows exploitation over standard HTTP or HTTPS interfaces exposed by Allegra.

Root Cause

The root cause is missing path canonicalization inside extractFileFromZip. The method trusts entry names from the archive and passes them into file write APIs without confirming that the resolved destination remains within the target directory. This is a textbook CWE-22 pattern often referred to as the Zip Slip class of vulnerabilities.

Attack Vector

An attacker with valid credentials to Allegra uploads a crafted ZIP archive through a feature that invokes extractFileFromZip. The archive contains at least one entry whose path traverses to a writable location outside the extraction root. Once written, the attacker triggers execution of the planted file through an application component or system scheduler that loads or runs the target path. The resulting code executes with the privileges of the Allegra service account.

Detailed technical information is available in the Zero Day Initiative Advisory ZDI-25-254.

Detection Methods for CVE-2025-3485

Indicators of Compromise

ZIP archives uploaded to Allegra containing entries with ../ or absolute paths in their file names
Unexpected files appearing outside the Allegra project data or attachment directories after archive imports
New or modified files in web-accessible directories, startup paths, or scheduled task directories on Allegra servers
Child processes spawned by the Allegra application process shortly after an authenticated file upload

Detection Strategies

Inspect Allegra application logs for file upload and ZIP import operations correlated with newly written files outside expected directories
Enable file integrity monitoring on the Allegra installation directory, web root, and system service paths
Review authentication logs for accounts performing archive uploads outside of expected user behavior baselines

Monitoring Recommendations

Alert on process creation events where the Allegra Java or web server process spawns shells, script interpreters, or system binaries
Monitor outbound network connections from the Allegra server that deviate from documented integrations
Track write operations to paths containing traversal sequences at the operating system audit layer

How to Mitigate CVE-2025-3485

Immediate Actions Required

Upgrade Allegra to version 8.1.2 or later, which addresses the improper path validation in extractFileFromZip
Restrict Allegra accounts with file upload privileges to trusted users and enforce strong authentication
Place Allegra instances behind authenticated network controls and remove exposure to untrusted networks where feasible
Audit the Allegra host for unauthorized files written outside expected directories since the last known-good backup

Patch Information

Alltena addressed this vulnerability in Allegra 8.1.2. Refer to the Alltena Release Notes 8.1.2 for the official fix details and upgrade guidance. Administrators should apply the update on all Allegra instances and validate the upgrade by confirming the version reported by the application.

Workarounds

If immediate patching is not possible, disable or restrict application features that accept ZIP archive uploads
Run the Allegra service under a least-privilege account so that any successful exploitation is confined in scope
Apply operating system level controls, such as SELinux or AppArmor profiles, to prevent the Allegra process from writing to sensitive paths

bash

# Verify installed Allegra version after upgrade
curl -s https://<allegra-host>/allegra/version | grep -i version

# Example least-privilege service unit override (Linux systemd)
# /etc/systemd/system/allegra.service.d/hardening.conf
[Service]
ProtectSystem=strict
ReadWritePaths=/var/lib/allegra
NoNewPrivileges=true
PrivateTmp=true