CVE-2026-126188 Active Storage: Possible local file disclosure in Active Storage video previews and analysis
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-126188?
CVE-2026-126188 is a low-severity vulnerability in rails, published on 10 Nov 2026.
Official 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.
Weakness: CWE-200
Which versions are affected by CVE-2026-126188?
2 open source packages ship an affected version, including activestorage.
| Package | Affected | Fixed in |
|---|---|---|
activestorage RubyGems | All versions | 8.0.5.2 |
activestorage RubyGems | From 8.1.0.beta1 | 8.1.4.1 |
How do I fix CVE-2026-126188?
Upgrade activestorage to a fixed version for your release line: 8.0.5.2 or 8.1.4.1.
Is CVE-2026-126188 being exploited?
There is no known exploitation of CVE-2026-126188 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-126188, GHSA-3f4q-8x5m-76v8, UBUNTU-CVE-2026-126188.