CVE-2021-40418 in DaVinci Resolve
Summary
by MITRE • 12/22/2021
When parsing a file that is submitted to the DPDecoder service as a job, the R3D SDK will mistakenly skip over the assignment of a property containing an object referring to a UUID that was parsed from a frame within the video container. Upon destruction of the object that owns it, the uninitialized member will be dereferenced and then destroyed using the object’s virtual destructor. Due to the object property being uninitialized, this can result in dereferencing an arbitrary pointer for the object’s virtual method table, which can result in code execution under the context of the application.
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Analysis
by VulDB Data Team • 12/26/2021
The vulnerability identified as CVE-2021-40418 resides within the R3D SDK's DPDecoder service implementation, specifically during the processing of video container files. This flaw represents a classic use-after-free vulnerability that manifests when the SDK parses media files submitted as jobs to the decoder service. The root cause stems from improper memory management during the parsing process where certain object properties fail to receive proper initialization, creating a dangerous scenario that can be exploited by malicious actors.
The technical mechanism of this vulnerability involves the SDK's handling of UUID references extracted from video frames during file parsing operations. When the DPDecoder service processes these files, it encounters a specific parsing path where a property containing an object reference to a UUID is not properly assigned during the processing flow. This uninitialized property subsequently gets destroyed during object cleanup operations, triggering a virtual destructor call on an improperly initialized object. The CWE-416 classification applies here as the system attempts to use memory after it has been freed, while the ATT&CK technique T1059.007 (Command and Scripting Interpreter: PowerShell) may be relevant for exploitation vectors that leverage such memory corruption vulnerabilities.
The operational impact of this vulnerability extends beyond simple application instability, as the uninitialized virtual method table pointer can lead to arbitrary code execution within the application context. This represents a severe privilege escalation risk since the malicious code would execute with the same permissions as the vulnerable application, potentially allowing attackers to gain unauthorized access to system resources, execute arbitrary commands, or compromise the integrity of the media processing pipeline. The vulnerability affects any system utilizing the R3D SDK for video file processing, particularly those handling untrusted input from external sources.
Mitigation strategies should focus on immediate code-level fixes including proper initialization of all object properties before use, implementing robust memory management practices, and adding input validation checks to prevent malformed video files from triggering the vulnerable code path. Additionally, organizations should consider applying patches from the software vendor as soon as available, implementing network segmentation to limit exposure, and monitoring for suspicious file processing activities that might indicate exploitation attempts. The ATT&CK framework suggests implementing process monitoring and anomaly detection to identify potential exploitation attempts through memory corruption techniques.