CVE-2026-73239 Overview
CVE-2026-73239 is an Insecure Direct Object Reference (IDOR) vulnerability in Apache Allura caused by missing permission checks on multiple Artifact types. The flaw affects Apache Allura versions before 1.19.1. Attackers can reference internal object identifiers and interact with Artifacts they should not be authorized to access, bypassing the application's intended access control model. The Apache Software Foundation released 1.19.1 to correct the missing authorization enforcement.
Critical Impact
Authenticated users can access or manipulate Artifacts belonging to other users or projects by directly referencing object identifiers, resulting in Broken Access Control [CWE-280].
Affected Products
- Apache Allura versions before 1.19.1
- Apache Allura projects hosting multiple Artifact types (tickets, wikis, discussions, code repositories)
- Self-hosted Allura deployments serving multi-tenant project workspaces
Discovery Timeline
- 2026-08-12 - CVE CVE-2026-73239 published to NVD
- 2026-08-12 - Last updated in NVD database
Technical Details for CVE-2026-73239
Vulnerability Analysis
Apache Allura is an open-source project hosting platform that manages multiple Artifact types including tickets, wiki pages, forum posts, and source code entities. Each Artifact is addressed by a unique identifier within the application's URL structure and API surface. The vulnerability arises because several Artifact handlers do not verify whether the requesting user holds the required permission for the referenced object before returning or modifying it.
An authenticated user who knows or guesses a valid Artifact identifier can submit direct requests to endpoints that operate on that object. The application processes the request based on the identifier alone, without evaluating project-level or Artifact-level access controls. The result is horizontal privilege escalation across tenants and, in some cases, exposure of restricted project data.
Root Cause
The root cause is missing permission-check logic in the request-handling pipeline for the affected Artifact types, categorized as [CWE-280] Improper Handling of Insufficient Permissions or Privileges. The controllers resolve the Artifact from user-supplied input and act on it without invoking Allura's authorization framework.
Attack Vector
Exploitation requires an authenticated session on the target Allura instance. The attacker enumerates or brute-forces Artifact identifiers and issues HTTP requests to the vulnerable endpoints. Because the flaw resides in server-side authorization, no special client tooling is required beyond a standard HTTP client. Details of the affected endpoints are described in the Apache Allura Release Notes and the Apache Mailing List Discussion.
Detection Methods for CVE-2026-73239
Indicators of Compromise
- Unexpected access patterns in Allura application logs showing a single authenticated account requesting Artifact IDs across multiple projects it does not belong to.
- Sequential or enumerative requests to Artifact URLs (/p/<project>/tickets/<id>, wiki, and discussion endpoints) originating from a single session.
- Modifications to Artifacts by users who are not listed as project members or contributors.
Detection Strategies
- Correlate Allura HTTP access logs with project membership data to identify cross-project Artifact access by non-members.
- Alert on high-rate iteration of numeric or sequential Artifact identifiers by a single account within a short time window.
- Baseline normal per-user Artifact access volume and flag deviations that suggest enumeration.
Monitoring Recommendations
- Forward Allura web server and application logs to a centralized logging platform for retention and query.
- Monitor authentication events alongside Artifact access events to reconstruct session activity end-to-end.
- Review audit trails for Artifact edits and comment additions performed by accounts outside the project's ACL.
How to Mitigate CVE-2026-73239
Immediate Actions Required
- Upgrade all Apache Allura instances to version 1.19.1 or later without delay.
- Audit recent Artifact access and modification logs for evidence of cross-project activity by non-privileged accounts.
- Rotate credentials and revoke sessions for accounts suspected of enumerating Artifact identifiers.
Patch Information
Apache has released Allura 1.19.1, which adds the missing permission checks for the affected Artifact types. Administrators should follow the upgrade procedure documented in the Apache Allura Release Notes and review the coordinated disclosure notice in the Openwall OSS-Security Post.
Workarounds
- Restrict Allura access to trusted users only until the upgrade is applied, reducing the population of accounts able to exploit the IDOR.
- Place the Allura application behind a reverse proxy that enforces additional authentication controls on Artifact endpoints.
- Disable or gate self-service account registration to prevent unauthenticated adversaries from acquiring valid sessions.
# Configuration example: upgrade Apache Allura using pip
pip install --upgrade 'Allura==1.19.1'
# Verify the installed version after upgrade
pip show Allura | grep -i version
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
