CVE-2026-120210 in FFmpeg
Summary
by MITRE • 10/31/2026
FFmpeg 5.0 through 9.0.2 contains a path traversal vulnerability in the IMF demuxer that allows attackers to open files outside the package via unvalidated ASSETMAP Path elements. Attackers can supply a crafted IMF package with '..' or absolute paths to demux local MXF files, probe file existence and size, or trigger server-side requests.
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Analysis
by VulDB Data Team • 10/31/2026
The vulnerability identified in FFmpeg versions 5.0 through 9.0.2 resides within the Interoperability Master Format, commonly known as IMF, demuxer module. This component is responsible for parsing and extracting media data from IMF packages, which are standardized containers used extensively in professional broadcast and post-production workflows to store high-quality video, audio, and associated metadata. The core technical flaw stems from insufficient validation of path elements within the ASSETMAP XML file contained inside an IMF package. Specifically, the demuxer fails to properly sanitize or restrict paths specified for asset references, allowing attackers to inject directory traversal sequences such as double dots followed by a slash (.. /) or absolute filesystem paths into these fields. This lack of input validation enables the application to resolve file locations outside the intended scope of the IMF package structure.
From an operational perspective, this path traversal vulnerability allows malicious actors to read arbitrary files from the host system where FFmpeg is executing. By crafting a specialized IMF package with manipulated ASSETMAP entries, an attacker can direct the demuxer to access local MXF files or other sensitive data stored on the server's filesystem. Beyond simple file reading, the ability to probe for specific file existence and determine their size provides reconnaissance capabilities that can aid in further exploitation attempts against the underlying infrastructure. Furthermore, if FFmpeg is deployed in a server-side context where it processes untrusted media uploads, this flaw can be leveraged to trigger Server-Side Request Forgery (SSRF) attacks. In such scenarios, the application may initiate network requests to internal or external resources based on the crafted paths, potentially exposing internal services or facilitating data exfiltration through out-of-band channels.
This vulnerability aligns with CWE-22: Improper Limitation of a Pathname to a Restricted Directory, which describes flaws where software does not properly neutralize special elements within a pathname that can cause the path to resolve to a location outside of the restricted directory. Additionally, the potential for triggering server-side requests maps directly to MITRE ATT&CK technique T1560: Archive Collected Data, specifically when used in conjunction with data staging or exfiltration methods, and potentially T1048: Exfiltration Over Alternative Protocol if network-based exploitation is utilized. The impact ranges from information disclosure of sensitive local files to potential remote code execution depending on the broader application context and available exploit chains involving the accessed resources.
Mitigation strategies should prioritize upgrading FFmpeg to a version beyond 9.0.2 where this path traversal issue has been addressed by developers through stricter input validation and canonicalization checks within the IMF demuxer logic. For environments that cannot immediately upgrade, implementing strict allowlists for file extensions and paths at the application layer can provide an additional defense-in-depth measure. It is also recommended to run FFmpeg processes with minimal privileges using sandboxing techniques or containerization limits such as Linux namespaces and cgroups to restrict filesystem access even if a traversal occurs. Network segmentation should be employed to limit the ability of compromised media processing services to initiate unauthorized outbound connections, thereby mitigating the SSRF risk associated with this vulnerability.