FFmpeg CVE-2026-107697

Requires a victim application or service that uses FFmpeg's HLS demuxer to process an attacker-supplied master playlist (UI:P - a user or automated pipeline must open/ingest the malicious playlist). The specific trigger is a master playlist whose child playlists reference disallowed protocols or non-multimedia local files, which parse_playlist() opens despite the HLS security policy. Limiting factors: exploitation is bounded to confidentiality (reading restricted resources/files) with no integrity or availability impact; it depends on the target actually feeding untrusted HLS input to FFmpeg and on the demuxer being reachable; affected versions are FFmpeg before 8.1.3, so patched builds are not vulnerable.

This is a genuine but moderate-severity issue rather than a top-priority emergency. The vendor-assigned CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N) describes a network-reachable, low-complexity, unauthenticated bypass that nonetheless requires passive user/service interaction (UI:P) and yields only limited confidentiality impact with no integrity or availability loss - consistent with a security-policy bypass (CWE-693) that enables reading disallowed local files or reaching restricted protocols rather than code execution. No EPSS score, SSVC decision, KEV listing, or POC was provided in the input, so there is no public exploit identified at time of analysis and no evidence of active exploitation; the finding originates from a credible researcher (VulnCheck) and a patch is available. The practical risk is therefore driven by FFmpeg's enormous deployment footprint and its frequent use to process untrusted media, not by raw score: any service that auto-ingests attacker-supplied HLS master playlists is exposed to SSRF-style and local-file-disclosure behavior. Note a signal gap: the input provides only a CVSS 4.0 vector (no 3.1 vector, no EPSS, no KEV/SSVC), so exploitation-probability signals are missing and risk is inferred from the vector and code evidence rather than confirmed exploitation telemetry.

An attacker hosts or submits a crafted HLS master playlist to a service that uses FFmpeg to demux media. When FFmpeg's HLS demuxer parses the child playlists, parse_playlist() opens URLs that should be blocked by the allowed_extensions/protocol policy, letting the attacker point the demuxer at local files (e.g. config or non-multimedia files) or disallowed protocols and leak their contents back through the media pipeline. No public exploit code was identified in the provided data, but the root-cause commit (switching io_open to open_url) makes the bypass straightforward to reproduce.