CVE-2022-39236 in matrix-js-sdk
Summary
by MITRE • 09/28/2022
Matrix Javascript SDK is the Matrix Client-Server SDK for JavaScript. Starting with version 17.1.0-rc.1, improperly formed beacon events can disrupt or impede the matrix-js-sdk from functioning properly, potentially impacting the consumer's ability to process data safely. Note that the matrix-js-sdk can appear to be operating normally but be excluding or corrupting runtime data presented to the consumer. This is patched in matrix-js-sdk v19.7.0. Redacting applicable events, waiting for the sync processor to store data, and restarting the client are possible workarounds. Alternatively, redacting the applicable events and clearing all storage will fix the further perceived issues. Downgrading to an unaffected version, noting that such a version may be subject to other vulnerabilities, will additionally resolve the issue.
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Analysis
by VulDB Data Team • 10/15/2024
The CVE-2022-39236 vulnerability affects the Matrix JavaScript SDK, a client-server SDK for JavaScript that enables communication within the Matrix decentralized communication protocol. This security flaw emerged in versions 17.1.0-rc.1 and later, specifically targeting how the SDK handles beacon events which are used to share location data and other real-time information within Matrix rooms. The vulnerability represents a significant concern for developers and end-users relying on Matrix-based applications for secure communication and data exchange. The issue stems from inadequate input validation mechanisms within the SDK's event processing pipeline, creating a condition where malformed beacon events can cause unexpected behavior in the client application's data handling processes.
The technical implementation of this vulnerability occurs when the matrix-js-sdk encounters improperly formed beacon events that do not conform to expected data structures or validation rules. These malformed events trigger a cascade of issues within the SDK's synchronization processor, which is responsible for maintaining consistent state between the client and the Matrix server. The vulnerability manifests as data corruption or exclusion rather than complete system failure, making it particularly insidious since the SDK may appear to function normally while silently corrupting or omitting critical runtime data. This behavior aligns with CWE-20, "Improper Input Validation," and represents a classic case of insufficient sanitization of user-provided data within a client-side application framework. The flaw essentially allows malicious or malformed data to disrupt the normal operation of the client without causing an outright crash, leading to data integrity issues that can compromise the security and reliability of Matrix-based communications.
The operational impact of CVE-2022-39236 extends beyond simple data corruption, potentially affecting the integrity of real-time communication systems that depend on accurate location and status information. When beacon events are improperly handled, users may experience inconsistent room state information, missing location updates, or corrupted message histories that can severely impact collaboration and communication workflows. The vulnerability's stealthy nature means that administrators and developers might not immediately recognize the issue, as the SDK continues to operate but with compromised data integrity. This characteristic places the vulnerability in the ATT&CK framework under T1070.004, "Indicator Removal on Host," since the corrupted data may not be immediately apparent to users, potentially masking other security issues or communication problems that could affect the overall security posture of Matrix-based applications.
The recommended mitigations for this vulnerability include several approaches that address different aspects of the data corruption issue. The most straightforward solution involves applying the official patch in matrix-js-sdk version 19.7.0, which implements proper validation and error handling for beacon events. Alternative workarounds include redacting problematic events and allowing the sync processor to store data, followed by client restarts, which can temporarily resolve the issue by clearing corrupted state information. More comprehensive fixes involve redacting affected events and clearing all client storage, which ensures a clean slate for data processing and prevents further corruption. Organizations may also consider downgrading to unaffected versions, though this approach introduces additional security risks since older versions may contain other unpatched vulnerabilities. The vulnerability demonstrates the importance of robust input validation in client-side frameworks and highlights the need for comprehensive testing of data handling mechanisms in decentralized communication systems. This issue underscores the critical relationship between proper event validation and data integrity in real-time collaborative environments, where even subtle data corruption can significantly impact user experience and system reliability.