CVE-2026-107697 in FFmpeg
Summary
by MITRE • 10/08/2026
FFmpeg before 8.1.3 contains a protection mechanism failure in the HLS demuxer that allows attackers to bypass protocol and allowed_extensions restrictions when opening child playlists. Attackers can supply a crafted master playlist whose child playlists use disallowed protocols or non-multimedia local files, making parse_playlist() open resources the HLS security policy should block.
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Analysis
by VulDB Data Team • 10/08/2026
The vulnerability identified in FFmpeg versions prior to 8.1.3 represents a critical failure in access control mechanisms within the HTTP Live Streaming demuxer component. This flaw specifically affects how the application handles master playlists and their associated child playlist resources, allowing attackers to circumvent established security policies designed to restrict resource types and protocols. The core issue lies in the parse_playlist function, which is responsible for processing HLS manifest files. When a crafted master playlist is provided, it can reference child playlists that utilize disallowed network protocols or point to non-multimedia local file system resources. Under normal operational parameters, FFmpeg should enforce strict adherence to configured allowed_extensions and protocol restrictions, thereby blocking access to unauthorized or potentially dangerous resources. However, due to the protection mechanism failure, these safeguards are effectively bypassed during the parsing phase of child playlists embedded within a master playlist structure.
From a technical perspective, this vulnerability stems from insufficient validation logic when resolving relative paths or external references within HLS manifests. The demuxer fails to properly sanitize or verify the protocol scheme and file extension attributes before attempting to open these resources for reading. This lack of rigorous input validation enables an attacker to construct a malicious master playlist that directs FFmpeg to load content via protocols such as file://, ftp://, or other restricted schemes, even if only http:// or https:// are permitted by configuration. Furthermore, the ability to reference local files allows for potential information disclosure scenarios where sensitive data residing on the host system can be exfiltrated through the media processing pipeline. The flaw essentially treats all referenced resources as valid multimedia content without applying the expected security filters that would normally restrict access based on predefined allowlists or denylists.
The operational impact of this vulnerability is significant, particularly for applications and services that process user-supplied HLS streams. Attackers can leverage this weakness to perform unauthorized file reads from the local filesystem where FFmpeg is executed, leading to potential data leakage of sensitive configuration files, credentials, or private documents stored in accessible directories. Additionally, if the application allows remote interaction with the demuxer, an attacker could potentially trigger denial-of-service conditions by forcing the system to attempt opening non-existent or restricted resources, causing crashes or resource exhaustion. In environments where FFmpeg is used for automated media processing pipelines, this vulnerability compromises the integrity of the security boundary between untrusted input and trusted local storage, undermining trust in the application's ability to safely handle external content.
This issue aligns with CWE-284 Improper Access Control, as it involves a failure to enforce proper restrictions on authorized interactions with resources. It also relates to CWE-798 Use of Hard-coded Credentials if the accessed files contain sensitive information, and potentially CWE-200 Exposure of Sensitive Information to an Unauthorized Actor when local files are read without authorization. From an adversarial tactics perspective, this vulnerability supports ATT&CK technique T1530 Data from Local System Retrieval, as it enables attackers to access data stored on the victim's system through a legitimate application component. Mitigation strategies primarily involve upgrading FFmpeg to version 8.1.3 or later where these validation checks have been strengthened. For systems unable to upgrade immediately, implementing strict input sanitization at the application layer before passing HLS manifests to the library is recommended. Additionally, running FFmpeg in a sandboxed environment with restricted filesystem permissions can limit the blast radius of any successful exploitation attempts by preventing access to critical system directories and sensitive user files.