CVE-2013-0850 in FFmpeg
Summary
by MITRE
The decode_slice_header function in libavcodec/h264.c in FFmpeg before 1.1 allows remote attackers to have an unspecified impact via crafted H.264 data, which triggers an out-of-bounds array access.
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Analysis
by VulDB Data Team • 05/17/2021
The vulnerability identified as CVE-2013-0850 represents a critical buffer overflow condition within the FFmpeg multimedia framework's H.264 video decoding implementation. This flaw exists in the decode_slice_header function located in libavcodec/h264.c file of FFmpeg versions prior to 1.1. The vulnerability arises when processing specially crafted H.264 video streams that contain malformed slice header data, creating a scenario where the decoder attempts to access memory locations beyond the bounds of allocated arrays. Such out-of-bounds memory access can lead to unpredictable behavior including application crashes, memory corruption, or potentially arbitrary code execution depending on the specific memory layout and exploitation circumstances.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and represents a classic buffer overflow scenario where insufficient input validation allows attackers to manipulate memory access patterns. The flaw specifically affects the H.264 video decoding pipeline, making it particularly dangerous in environments where FFmpeg processes untrusted video content from various sources. Attackers can craft malicious H.264 streams that, when processed by vulnerable FFmpeg implementations, trigger the out-of-bounds array access during slice header decoding operations. This vulnerability demonstrates the inherent complexity of video codec implementations and the challenges of safely parsing structured multimedia data formats that can contain numerous variable-length fields and complex encoding parameters.
From an operational impact perspective, this vulnerability presents significant security risks across multiple attack vectors since FFmpeg is widely deployed in media processing applications, content delivery networks, streaming services, and multimedia frameworks. The unspecified impact mentioned in the CVE description suggests that exploitation could potentially lead to denial of service conditions or more severe outcomes including remote code execution depending on the execution environment and memory corruption patterns. The vulnerability affects systems that process H.264 video content from untrusted sources, making it particularly dangerous in web applications, media servers, and any system that relies on FFmpeg for video transcoding or playback. This type of vulnerability is especially concerning in enterprise environments where media processing systems handle large volumes of user-generated content or third-party media files.
The mitigation strategy for CVE-2013-0850 primarily involves upgrading to FFmpeg version 1.1 or later, where the buffer overflow condition has been addressed through proper bounds checking and input validation. Organizations should also implement defensive measures such as input sanitization, content filtering, and restricted processing of untrusted media files. Network-based defenses can include implementing media validation proxies that scan incoming video content for malformed H.264 streams before processing. From an ATT&CK framework perspective, this vulnerability maps to techniques involving code injection and privilege escalation through software exploitation, specifically targeting the execution of malicious code within legitimate media processing applications. Security teams should also consider implementing monitoring for unusual memory access patterns and application crashes that might indicate exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date multimedia libraries and implementing robust input validation mechanisms in all media processing pipelines to prevent similar issues from occurring in other components of the multimedia stack.