Can you explain this vulnerability to me?

[{'type': 'paragraph', 'content': "CVE-2026-27973 is a stored cross-site scripting (XSS) vulnerability in the Audiobookshelf mobile application versions prior to 0.12.0-beta and server versions prior to 2.12.0. The vulnerability exists in the way the app renders audiobook metadata in search results using Vue's v-html directive without properly sanitizing the content. This allows an attacker with privileges to modify library metadata to inject malicious JavaScript code into fields like title or author."}, {'type': 'paragraph', 'content': "When a victim user performs a search that triggers the rendering of this malicious metadata, the injected JavaScript executes in the victim's browser or WebView. This can lead to session hijacking, data theft, and unauthorized access to device APIs."}] [2]

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How can this vulnerability impact me? :

This vulnerability can impact users by allowing attackers to execute arbitrary JavaScript code in their browsers or app WebViews. Potential impacts include:

• Session hijacking, where attackers steal session tokens to impersonate users.
• Data exfiltration, such as stealing sensitive information stored locally like tokens.
• Unauthorized access to native device APIs, potentially compromising device security.

Exploitation requires the attacker to have high privileges to modify library metadata and the victim to perform a search that triggers the malicious content rendering.

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How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:

I don't know

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How can this vulnerability be detected on my network or system? Can you suggest some commands?

[{'type': 'paragraph', 'content': 'This vulnerability can be detected by checking if your Audiobookshelf mobile application or server is running a vulnerable version (mobile app ≤ 0.11.0-beta, server ≤ 2.11.0) and by inspecting if malicious library metadata containing JavaScript payloads exists.'}, {'type': 'paragraph', 'content': 'One practical approach is to search the audiobook library metadata for suspicious HTML or JavaScript code, such as tags with event handlers (e.g., <img src=x onerror=alert(...)>).'}, {'type': 'paragraph', 'content': 'Since the vulnerability triggers when a user performs a search that renders malicious metadata, you can perform searches on your system to detect if any metadata contains unsafe HTML.'}, {'type': 'paragraph', 'content': 'Specific commands depend on your environment, but for example, if you have access to the database or metadata files, you can use grep or similar tools to find suspicious patterns:'}, {'type': 'list_item', 'content': "grep -r -i '<script' /path/to/audiobookshelf/metadata"}, {'type': 'list_item', 'content': "grep -r -i 'onerror=' /path/to/audiobookshelf/metadata"}, {'type': 'list_item', 'content': "grep -r -i '<img' /path/to/audiobookshelf/metadata"}, {'type': 'paragraph', 'content': 'Additionally, monitoring network traffic for suspicious payloads or unexpected HTML content in search API responses could help detect exploitation attempts.'}] [2]

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What immediate steps should I take to mitigate this vulnerability?

The immediate and most effective mitigation is to upgrade your Audiobookshelf mobile application to version 0.12.0-beta or later and the server to version 2.12.0 or later, where the vulnerability has been fixed.

If upgrading is not immediately possible, restrict or remove library modification privileges from untrusted users to prevent attackers from injecting malicious metadata.

Avoid performing searches that could trigger rendering of malicious metadata until the system is patched.

Consider sanitizing or manually reviewing and cleaning existing audiobook metadata to remove any potentially malicious HTML or JavaScript content.

Implement network monitoring to detect suspicious activity related to this vulnerability.

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