Affected: Homebrew: streamlink

Streamlink is a CLI utility which pipes video streams from various services into a video player. Prior to 8.4.0, Streamlink's HLS and DASH parsers do not validate the URI scheme of segment entries and other resources. A remote .m3u8 HLS playlist or .mpd DASH manifest can list file:///path/to/file as a segment, and streamlink will read that local file and write its contents to the output stream. This vulnerability is fixed in 8.4.0.

Streamlink is a CLI utility which pipes video streams from various services into a video player. Prior to 8.4.0, Streamlink's HLS and DASH parsers do not validate the URI scheme of segment entries and other resources. A remote .m3u8 HLS playlist or .mpd DASH manifest can list file:///path/to/file as a segment, and streamlink will read that local file and write its contents to the output stream. This vulnerability is fixed in 8.4.0.

Affected: PyPI: streamlink

## Summary

Streamlink's HLS and DASH parsers do not validate the URI scheme of segment entries and other resources. A remote `.m3u8` HLS playlist or `.mpd` DASH manifest can list `file:///path/to/file` as a segment, and streamlink will read that local file and write its contents to the output stream.

Confirmed on streamlink 8.3.0 (latest release at time of report).

## Description

Segment URIs from an HLS playlist or DASH manifest are passed to the worker without any scheme check. The underlying HTTP session accepts `file://` URIs, which resolve against the local filesystem. There is no scheme allowlist at the parser level, so any path readable by the streamlink process is treated as a valid segment.

The attacker does not need local access to the victim. A playlist/manifest hosted on an attacker-controlled server, fetched by streamlink on the victim's machine, is enough to trigger the read.

## Impact

A remote attacker hosting a malicious playlist/manifest can make any client running streamlink against that URL read arbitrary local files within the streamlink process's read scope and write them into the output file.

Reachable files depend on the user running streamlink. Typical targets: `~/.ssh/id_*` private keys, `~/.aws/credentials`, shell history, application config files holding API tokens, and world-readable system files like `/etc/passwd`.

### Affected scenarios

- Server-side or automated deployments (recording bots, media pipelines, CI jobs processing playlist…

streamlink-8.4.0-1.1 on GA media

Affected: PyPI: streamlink

Streamlink is a CLI utility which pipes video streams from various services into a video player. Prior to 8.4.0, Streamlink's HLS and DASH parsers do not validate the URI scheme of segment entries and other resources. A remote .m3u8 HLS playlist or .mpd DASH manifest can list file:///path/to/file as a segment, and streamlink will read that local file and write its contents to the output stream. This vulnerability is fixed in 8.4.0.

Affected: Ubuntu:18.04:LTS: streamlink, Ubuntu:20.04:LTS: streamlink, Ubuntu:22.04:LTS: streamlink, Ubuntu:24.04:LTS: streamlink, Ubuntu:25.10: streamlink, Ubuntu:26.04:LTS: streamlink

Streamlink is a CLI utility which pipes video streams from various services into a video player. Prior to 8.4.0, Streamlink's HLS and DASH parsers do not validate the URI scheme of segment entries and other resources. A remote .m3u8 HLS playlist or .mpd DASH manifest can list file:///path/to/file as a segment, and streamlink will read that local file and write its contents to the output stream. This vulnerability is fixed in 8.4.0.