CVE-2026-73240: Apache Allura Git Argument Injection

CVE-2026-73240 Overview

CVE-2026-73240 is a git argument injection vulnerability in Apache Allura, an open-source project management and collaboration platform. Specifically crafted inputs can be passed through to underlying git command invocations, allowing attackers to inject unintended arguments. The flaw is classified under CWE-88: Improper Neutralization of Argument Delimiters in a Command. All versions of Apache Allura prior to 1.19.1 are affected. The Apache Allura project has released version 1.19.1 to remediate the issue.

Critical Impact
Attackers who supply crafted inputs to Allura endpoints that invoke git can inject additional command-line arguments, potentially leading to unintended repository operations or further command abuse.

Affected Products

Apache Allura versions prior to 1.19.1
Deployments integrating Allura with git-backed source code repositories
Self-hosted Allura instances used for forge and project management workflows

Discovery Timeline

2026-08-12 - CVE-2026-73240 published to NVD
2026-08-12 - Last updated in NVD database
2026-08-12 - Openwall OSS-Security advisory published

Technical Details for CVE-2026-73240

Vulnerability Analysis

Apache Allura constructs git command invocations that incorporate user-controllable input. When that input is not properly neutralized, attackers can supply values that the git binary interprets as additional command-line arguments rather than as data. This class of flaw is tracked as CWE-88 argument injection and is distinct from full command injection because the shell is not necessarily invoked. The attacker instead abuses git's own argument parsing, including options that can alter repository behavior, expose data, or influence how references and files are handled. Consult the Apache Allura 1.19.1 release notes and the Apache mailing list discussion for project-provided technical context.

Root Cause

The root cause is missing or insufficient sanitization of input that flows into git command arguments. Inputs beginning with a leading dash or containing option-like tokens are treated by git as switches. Without input validation or use of the -- argument terminator, Allura passes attacker-controlled tokens directly to the process invocation.

Attack Vector

An attacker submits crafted input through an Allura interface or API that ultimately reaches a git subprocess. Because the input is interpreted as an argument, the attacker can toggle git options, redirect operations, or influence execution context. The precise attack surface and privilege requirements depend on which Allura workflows the deployment exposes to unauthenticated or low-privileged users.

No verified proof-of-concept code has been published. Refer to the Openwall OSS-Security update for coordinated disclosure details.

Detection Methods for CVE-2026-73240

Indicators of Compromise

Apache Allura process trees where git is invoked with unexpected leading-dash arguments derived from HTTP request parameters
Web access logs containing request parameters that begin with - or -- targeting Allura repository, ticket, or wiki endpoints
Unexpected git operations such as pushes, config changes, or upload-pack requests originating from the Allura service account

Detection Strategies

Inventory all Apache Allura installations and compare deployed versions against the fixed release 1.19.1
Instrument the Allura host to log full argv for every child git process and alert on argument tokens that look like options but were not emitted by Allura itself
Correlate HTTP request payloads with subsequent git subprocess execution to identify suspicious input-to-argument flows

Monitoring Recommendations

Forward Allura application logs, web server logs, and process execution telemetry to a centralized analytics platform for retention and query
Alert on anomalous git subcommands (for example, upload-pack, receive-pack, or config) initiated by the Allura service account outside of normal usage patterns
Monitor outbound network connections from Allura hosts for unexpected git remote fetches or pushes

How to Mitigate CVE-2026-73240

Immediate Actions Required

Upgrade Apache Allura to version 1.19.1 or later as recommended by the project
Restrict network exposure of Allura administrative and repository endpoints to trusted networks until patching is complete
Review Allura audit logs and git operation history for signs of prior exploitation

Patch Information

Apache has released Apache Allura 1.19.1, which remediates the git argument injection issue. Upgrade instructions and change details are available in the Apache Allura 1.19.1 release notes. Additional advisory context is available on the Apache mailing list and the Openwall OSS-Security list.

Workarounds

If immediate upgrade is not possible, restrict access to Allura features that trigger server-side git operations to authenticated, trusted users only
Place Allura behind a reverse proxy or web application firewall that rejects request parameters beginning with - in fields feeding repository operations
Run the Allura service under a least-privileged account with no write access outside the intended repository directories

bash

# Upgrade Apache Allura to the fixed release
pip install --upgrade 'Allura>=1.19.1'

# Verify the installed version
python -c "import allura; print(allura.__version__)"