CVE-2026-52297 in FFmpeg
Summary
by MITRE • 09/14/2026
FFmpeg before 9.0 has an out-of-bounds read because there is insufficiently padded extradata in the MOV parsing path in mov_read_iacb in libavformat/mov.c.
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Analysis
by VulDB Data Team • 09/14/2026
The vulnerability identified in FFmpeg versions prior to release 9.0 represents a critical memory safety issue within the multimedia processing framework, specifically located in the container format handling logic for QuickTime and MP4 files. This flaw manifests as an out-of-bounds read operation triggered during the parsing of MOV file structures. The root cause lies in the function mov_read_iacb found within the libavformat/mov.c source module, which is responsible for processing specific metadata atoms or boxes within the container format. When FFmpeg encounters a malformed or specially crafted media file where the extradata associated with certain streams lacks sufficient padding, the parser fails to correctly validate buffer boundaries before attempting to read data structures that rely on this padded region. This insufficient validation allows the application to access memory locations beyond the allocated buffer limits, leading to an out-of-bounds read condition.
From a technical perspective, this vulnerability falls under the category of improper input validation and boundary checking errors. In the context of industry-standard classification systems such as CWE (Common Weakness Enumeration), this flaw aligns with CWE-125: Out-of-bounds Read. The issue arises because the parser assumes that certain data structures will always be followed by a specific amount of padding or null bytes, which is not guaranteed in all valid or maliciously crafted files. When an attacker provides a file where these assumptions do not hold, the memory read operation extends into adjacent heap or stack memory regions. While out-of-bounds reads are generally less severe than buffer overflows that allow for arbitrary code execution, they can still lead to significant security and stability issues depending on what data is exposed from those adjacent memory locations.
The operational impact of this vulnerability primarily centers around information disclosure and potential denial of service conditions. If the out-of-bounds read accesses sensitive memory contents such as cryptographic keys, session tokens, or other private user data previously stored in nearby heap allocations, it could result in a leak of confidential information to an attacker who controls the input file. Furthermore, accessing invalid memory addresses can cause the application to crash due to segmentation faults or access violations, leading to a denial of service for users relying on FFmpeg-based applications to process media files. In complex deployment scenarios where FFmpeg is used as a library within larger services, such crashes could disrupt critical workflows and degrade system availability. Although direct remote code execution via an out-of-bounds read alone is rare without additional exploitation techniques like heap spraying or specific memory layout control, the presence of this flaw significantly expands the attack surface by providing potential avenues for further exploitation if combined with other vulnerabilities in the same processing pipeline.
Mitigation strategies for this vulnerability involve immediate software updates and defensive coding practices. The primary remediation step is to upgrade FFmpeg to version 9.0 or later, where developers have addressed the insufficient padding checks within the mov_read_iacb function by implementing stricter boundary validations before accessing extradata regions. For organizations unable to update immediately due to dependency constraints, applying vendor-provided patches if available and restricting input sources to trusted parties can reduce exposure risk. Additionally, integrating fuzzing tools into continuous integration pipelines that specifically target MOV/MP4 parsing logic can help identify similar edge cases in custom builds or forks of FFmpeg. Security teams should also consider deploying runtime protection mechanisms such as Address Sanitizer (ASan) during testing phases and memory-safe wrappers in production environments to detect and mitigate out-of-bounds access attempts before they result in successful exploitation.
In terms of threat modeling, this vulnerability can be mapped to the MITRE ATT&CK framework under techniques related to collection or discovery if used for information leakage, though it is more accurately categorized as a general software weakness rather than an active attack technique until exploited. The lack of robust input validation on container format metadata highlights the importance of rigorous security testing in multimedia libraries that handle untrusted inputs from diverse sources. Developers working with FFmpeg should prioritize validating all structural assumptions about file formats and ensure that buffer sizes are dynamically calculated based on actual content length rather than relying on implicit padding conventions that may not hold true for maliciously constructed files.