Description

XSS vulnerability in code display in Apache Allura. This issue affects Apache Allura: before 1.19.1. Users are recommended to upgrade to version 1.19.1, which fixes the issue.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.1",
  "pubDate": "2026-08-12T17:17:32.080Z",
  "pubdate": "2026-08-12T17:17:32.080Z",
  "executiveSummary": "A Cross-Site Scripting (XSS) vulnerability exists in the code display functionality of Apache Allura prior to version 1.19.1. This security flaw allows malicious actors to inject arbitrary client-side scripts, typically JavaScript, into web pages rendered by the application. When targeted users view the compromised code display interface, the injected scripts execute within the context of their session, leading to potential session hijacking, unauthorized actions performed on behalf of the victim, or the exfiltration of sensitive user data. The vulnerability impacts all deployments of Apache Allura running versions prior to 1.19.1. The risk implication is moderate to high depending on the privileges of the affected user interacting with the malicious payload. Exploitation generally requires a user to navigate to or interact with a crafted repository file or code view rendered insecurely by the application. To mitigate this risk, administrators and system operators must promptly apply the official software update provided by the vendor, ensuring all instances are upgraded to version 1.19.1 or later where the underlying sanitization and rendering logic has been corrected.",
  "technicalDetails": "The vulnerability resides within the code display component of Apache Allura, specifically affecting versions prior to 1.19.1. The root cause stems from improper input sanitization and insufficient context-aware output encoding when rendering repository files or code snippets within the web interface. When untrusted input containing malicious markup or script tags is processed and reflected directly into the Document Object Model (DOM) without adequate escaping, the browser interprets the input as executable code rather than plain text.\nThe attack flow begins when an authenticated or unauthenticated attacker (depending on repository access controls) introduces specially crafted payloads into a codebase or file processed by Apache Allura. This payload is designed to bypass weak filters or exploit missing encoding routines in the code viewer. When a victim accesses the affected code display page, the server responds with the unescaped malicious payload embedded within the HTML document structure.\nUpon receiving the response, the victim's browser parses the HTML and executes the embedded script within the security context of the vulnerable origin. This enables the execution of arbitrary JavaScript capable of accessing document properties, manipulating the DOM, stealing session cookies, or performing unauthorized API requests using the victim's session credentials. Network exposure is inherent to any web-accessible deployment of Apache Allura. The vulnerability requires no specialized privileges beyond the ability to view the vulnerable code display interface, though successful payload delivery often relies on the ability to commit malicious code to a repository or manipulate displayed source files. Remediation requires updating the affected codebase to version 1.19.1 to enforce proper output encoding and context-aware sanitization across all code rendering pathways."
}