CVE-2024-5693 in Firefox
Summary
by MITRE • 06/11/2024
Offscreen Canvas did not properly track cross-origin tainting, which could be used to access image data from another site in violation of same-origin policy. This vulnerability affects Firefox < 127 and Firefox ESR < 115.12.
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Analysis
by VulDB Data Team • 06/18/2025
The vulnerability identified as CVE-2024-5693 represents a critical security flaw in Firefox's handling of Offscreen Canvas functionality that undermines the fundamental same-origin policy protections inherent to web browsers. This issue specifically affects the cross-origin tainting mechanism that should prevent unauthorized access to image data from different origins. The flaw exists within Firefox versions prior to 127 and Firefox ESR versions prior to 115.12, creating a window of exposure for users who have not yet updated their browsers. The vulnerability demonstrates a failure in the browser's security model that allows for potential information disclosure and cross-site data access.
The technical root cause of this vulnerability lies in the improper tracking of cross-origin tainting within the Offscreen Canvas API implementation. When a web page attempts to access image data from a different origin through Offscreen Canvas operations, the browser should enforce strict tainting rules that prevent such access. However, the flaw allows for bypassing these protections, enabling malicious actors to extract image data from cross-origin resources that should be restricted. This occurs because the Offscreen Canvas implementation fails to properly maintain the tainting state that should be inherited from the source origin, creating a path for unauthorized data retrieval.
The operational impact of this vulnerability extends beyond simple information disclosure, as it represents a significant breach of web security boundaries that could enable more sophisticated attacks. An attacker could leverage this vulnerability to access sensitive image data from other domains, potentially including user profile pictures, authentication tokens embedded in images, or other cross-origin resources that contain confidential information. The vulnerability is particularly concerning because it operates at the rendering layer of the browser, making it difficult to detect through traditional network monitoring or application-layer security controls. This flaw could enable credential harvesting, session hijacking, or other advanced persistent threats that rely on accessing cross-origin resources.
Mitigation strategies for CVE-2024-5693 primarily focus on immediate browser updates to versions that contain the necessary security patches. System administrators and users should prioritize updating their Firefox installations to version 127 or later for regular releases, and version 115.12 or later for ESR releases. Additionally, organizations should implement network monitoring to detect potential exploitation attempts and consider deploying browser security extensions that provide additional layers of protection. The vulnerability aligns with CWE-200, which addresses improper exposure of sensitive information, and may be related to ATT&CK technique T1566 for credential access through web-based attacks. Organizations should also review their web application security policies to ensure proper implementation of CORS headers and other cross-origin resource sharing controls that complement browser-level protections.