CVE-2026-126188
Received
Received - Intake
Active Storage FFmpeg HLS File Disclosure via Preview
Vulnerability report for CVE-2026-126188, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-11-11
Last updated on: 2026-11-11
Assigner: GitHub, Inc.
Description
Description
Active Storage makes it simple to upload and reference files in cloud services and attach those files to Active Record objects. Prior to 8.0.5.2 and from 8.1 until 8.1.4.1, Active Storage's ActiveStorage::Previewer::VideoPreviewer, ActiveStorage::Analyzer::VideoAnalyzer, and ActiveStorage::Analyzer::AudioAnalyzer pass uploaded blob contents to FFmpeg without restricting the demuxer. A direct upload can retain a client-declared video/* or audio/* content type for an HLS playlist. FFmpeg content probing selects the hls demuxer, which opens attacker-named file:// segments when the blob is previewed or analyzed. Applications that accept untrusted uploads and generate video previews or analyze video or audio attachments can disclose a local media file readable by the application process when the attacker knows its path. This issue is fixed in versions 8.0.5.2 and 8.1.4.1.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| rails | active_storage | 8.0.5.2 |
| rails | active_storage | From 8.1 (inc) to 8.1.4.1 (exc) |
| rails | active_storage | 8.1.4.1 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-200 | The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. |
