# CVE-2026-126186: Active Storage: Possible arbitrary file read and remote code execution in Active Storage video previews, analysis and image processing

Status: published. Published: 2026-11-10. Updated: 2026-11-12.

Active Storage makes it simple to upload and reference files in cloud services and attach those files to Active Record objects. Prior to 8.1.4.1 and 8.0.5.2, ActiveStorage::Blob#open writes a blob to a tempfile whose name carries the extension of the uploaded filename, and hands that path to ffprobe (VideoAnalyzer, AudioAnalyzer), ffmpeg (VideoPreviewer) and ImageMagick (ImageAnalyzer, the :mini_magick variant processor). These tools select a decoder from the file extension when the content does not identify its own format, so an attacker who chooses the filename and declares the content type of an upload chooses which decoder processes it. An FFmpeg built with AviSynth support treats a file with the .avs extension as an AviSynth script and evaluates it, which could disclose files readable by the application process through the preview image, or load a native library the attacker has also uploaded, possibly leading to remote code execution in the FFmpeg process. ImageMagick selects its coders and delegates from the extension in the same way. An application is affected if it accepts uploads from untrusted users and analyzes video or audio attachments, generates video previews, or processes images with ImageMagick. The AviSynth attack additionally requires an FFmpeg built with --enable-avisynth and the AviSynthPlus runtime on the host. Upstream FFmpeg and the common Linux distribution and Homebrew packages do not enable it; the GPL builds distributed for Windows and Linux from ffmpeg.org do. Other decoders that FFmpeg or ImageMagick select from the extension may be reachable without AviSynth. This issue is fixed in versions 8.1.4.1 and 8.0.5.2.

## Remediation

- fix: activestorage (RubyGems): OSV reports a fixed version 8.1.4.1. Check the advisory for supported release branches. (source: OSV GHSA-v924-7rp8-4mxh) — https://github.com/advisories/GHSA-v924-7rp8-4mxh
- fix: activestorage (RubyGems): OSV reports a fixed version 8.0.5.2. Check the advisory for supported release branches. (source: OSV GHSA-v924-7rp8-4mxh) — https://github.com/advisories/GHSA-v924-7rp8-4mxh

## Affected products and versions

- rails / rails: >= 8.1, < 8.1.4.1 (affected); < 8.0.5.2 (affected). Source: CNA: GitHub_M
-  / activestorage (activestorage): 8.1.0 (affected, RubyGems); 8.1.0.beta1 (affected, RubyGems); 8.1.0.rc1 (affected, RubyGems); 8.1.1 (affected, RubyGems); 8.1.2 (affected, RubyGems); 8.1.2.1 (affected, RubyGems); 8.1.3 (affected, RubyGems); 8.1.3.1 (affected, RubyGems); 8.1.4 (affected, RubyGems); Ecosystem version events: introduced 8.1.0.beta1; fixed 8.1.4.1. Source: OSV GHSA-v924-7rp8-4mxh
-  / activestorage (activestorage): 0.1 (affected, RubyGems); 5.2.0 (affected, RubyGems); 5.2.0.beta1 (affected, RubyGems); 5.2.0.beta2 (affected, RubyGems); 5.2.0.rc1 (affected, RubyGems); 5.2.0.rc2 (affected, RubyGems); 5.2.1 (affected, RubyGems); 5.2.1.1 (affected, RubyGems); 5.2.1.rc1 (affected, RubyGems); 5.2.2 (affected, RubyGems); 5.2.2.1 (affected, RubyGems); 5.2.2.rc1 (affected, RubyGems); 5.2.3 (affected, RubyGems); 5.2.3.rc1 (affected, RubyGems); 5.2.4 (affected, RubyGems); 5.2.4.1 (affected, RubyGems); 5.2.4.2 (affected, RubyGems); 5.2.4.3 (affected, RubyGems); 5.2.4.4 (affected, RubyGems); 5.2.4.5 (affected, RubyGems); 5.2.4.6 (affected, RubyGems); 5.2.4.rc1 (affected, RubyGems); 5.2.5 (affected, RubyGems); 5.2.6 (affected, RubyGems); 5.2.6.1 (affected, RubyGems); 5.2.6.2 (affected, RubyGems); 5.2.6.3 (affected, RubyGems); 5.2.7 (affected, RubyGems); 5.2.7.1 (affected, RubyGems); 5.2.8 (affected, RubyGems); 5.2.8.1 (affected, RubyGems); 6.0.0 (affected, RubyGems); 6.0.0.beta1 (affected, RubyGems); 6.0.0.beta2 (affected, RubyGems); 6.0.0.beta3 (affected, RubyGems); 6.0.0.rc1 (affected, RubyGems); 6.0.0.rc2 (affected, RubyGems); 6.0.1 (affected, RubyGems); 6.0.1.rc1 (affected, RubyGems); 6.0.2 (affected, RubyGems); 6.0.2.1 (affected, RubyGems); 6.0.2.2 (affected, RubyGems); 6.0.2.rc1 (affected, RubyGems); 6.0.2.rc2 (affected, RubyGems); 6.0.3 (affected, RubyGems); 6.0.3.1 (affected, RubyGems); 6.0.3.2 (affected, RubyGems); 6.0.3.3 (affected, RubyGems); 6.0.3.4 (affected, RubyGems); 6.0.3.5 (affected, RubyGems); 6.0.3.6 (affected, RubyGems); 6.0.3.7 (affected, RubyGems); 6.0.3.rc1 (affected, RubyGems); 6.0.4 (affected, RubyGems); 6.0.4.1 (affected, RubyGems); 6.0.4.2 (affected, RubyGems); 6.0.4.3 (affected, RubyGems); 6.0.4.4 (affected, RubyGems); 6.0.4.5 (affected, RubyGems); 6.0.4.6 (affected, RubyGems); 6.0.4.7 (affected, RubyGems); 6.0.4.8 (affected, RubyGems); 6.0.5 (affected, RubyGems); 6.0.5.1 (affected, RubyGems); 6.0.6 (affected, RubyGems); 6.0.6.1 (affected, RubyGems); 6.1.0 (affected, RubyGems); 6.1.0.rc1 (affected, RubyGems); 6.1.0.rc2 (affected, RubyGems); 6.1.1 (affected, RubyGems); 6.1.2 (affected, RubyGems); 6.1.2.1 (affected, RubyGems); 6.1.3 (affected, RubyGems); 6.1.3.1 (affected, RubyGems); 6.1.3.2 (affected, RubyGems); 6.1.4 (affected, RubyGems); 6.1.4.1 (affected, RubyGems); 6.1.4.2 (affected, RubyGems); 6.1.4.3 (affected, RubyGems); 6.1.4.4 (affected, RubyGems); 6.1.4.5 (affected, RubyGems); 6.1.4.6 (affected, RubyGems); 6.1.4.7 (affected, RubyGems); 6.1.5 (affected, RubyGems); 6.1.5.1 (affected, RubyGems); 6.1.6 (affected, RubyGems); 6.1.6.1 (affected, RubyGems); 6.1.7 (affected, RubyGems); 6.1.7.1 (affected, RubyGems); 6.1.7.10 (affected, RubyGems); 6.1.7.2 (affected, RubyGems); 6.1.7.3 (affected, RubyGems); 6.1.7.4 (affected, RubyGems); 6.1.7.5 (affected, RubyGems); 6.1.7.6 (affected, RubyGems); 6.1.7.7 (affected, RubyGems); 6.1.7.8 (affected, RubyGems); 6.1.7.9 (affected, RubyGems); 7.0.0 (affected, RubyGems); 7.0.0.alpha1 (affected, RubyGems); 7.0.0.alpha2 (affected, RubyGems); 7.0.0.rc1 (affected, RubyGems); 7.0.0.rc2 (affected, RubyGems); 7.0.0.rc3 (affected, RubyGems); 7.0.1 (affected, RubyGems); 7.0.10 (affected, RubyGems); 7.0.2 (affected, RubyGems); 7.0.2.1 (affected, RubyGems); 7.0.2.2 (affected, RubyGems); 7.0.2.3 (affected, RubyGems); 7.0.2.4 (affected, RubyGems); 7.0.3 (affected, RubyGems); 7.0.3.1 (affected, RubyGems); 7.0.4 (affected, RubyGems); 7.0.4.1 (affected, RubyGems); 7.0.4.2 (affected, RubyGems); 7.0.4.3 (affected, RubyGems); 7.0.5 (affected, RubyGems); 7.0.5.1 (affected, RubyGems); 7.0.6 (affected, RubyGems); 7.0.7 (affected, RubyGems); 7.0.7.1 (affected, RubyGems); 7.0.7.2 (affected, RubyGems); 7.0.8 (affected, RubyGems); 7.0.8.1 (affected, RubyGems); 7.0.8.2 (affected, RubyGems); 7.0.8.3 (affected, RubyGems); 7.0.8.4 (affected, RubyGems); 7.0.8.5 (affected, RubyGems); 7.0.8.6 (affected, RubyGems); 7.0.8.7 (affected, RubyGems); 7.1.0 (affected, RubyGems); 7.1.0.beta1 (affected, RubyGems); 7.1.0.rc1 (affected, RubyGems); 7.1.0.rc2 (affected, RubyGems); 7.1.1 (affected, RubyGems); 7.1.2 (affected, RubyGems); 7.1.3 (affected, RubyGems); 7.1.3.1 (affected, RubyGems); 7.1.3.2 (affected, RubyGems); 7.1.3.3 (affected, RubyGems); 7.1.3.4 (affected, RubyGems); 7.1.4 (affected, RubyGems); 7.1.4.1 (affected, RubyGems); 7.1.4.2 (affected, RubyGems); 7.1.5 (affected, RubyGems); 7.1.5.1 (affected, RubyGems); 7.1.5.2 (affected, RubyGems); 7.1.6 (affected, RubyGems); 7.2.0 (affected, RubyGems); 7.2.0.beta1 (affected, RubyGems); 7.2.0.beta2 (affected, RubyGems); 7.2.0.beta3 (affected, RubyGems); 7.2.0.rc1 (affected, RubyGems); 7.2.1 (affected, RubyGems); 7.2.1.1 (affected, RubyGems); 7.2.1.2 (affected, RubyGems); 7.2.2 (affected, RubyGems); 7.2.2.1 (affected, RubyGems); 7.2.2.2 (affected, RubyGems); 7.2.3 (affected, RubyGems); 7.2.3.1 (affected, RubyGems); 7.2.3.2 (affected, RubyGems); 7.2.4 (affected, RubyGems); 8.0.0 (affected, RubyGems); 8.0.0.1 (affected, RubyGems); 8.0.0.beta1 (affected, RubyGems); 8.0.0.rc1 (affected, RubyGems); 8.0.0.rc2 (affected, RubyGems); 8.0.1 (affected, RubyGems); 8.0.2 (affected, RubyGems); 8.0.2.1 (affected, RubyGems); 8.0.3 (affected, RubyGems); 8.0.4 (affected, RubyGems); 8.0.4.1 (affected, RubyGems); 8.0.5 (affected, RubyGems); 8.0.5.1 (affected, RubyGems); Ecosystem version events: introduced 0; fixed 8.0.5.2. Source: OSV GHSA-v924-7rp8-4mxh

## Severity and prioritization

- CVSS 3.1: 8.8 (high); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H; source: CNA: GitHub_M

- CVSS 3.1: 8.8 (high); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H; source: NVD: security-advisories@github.com

- CISA KEV: No listing in collected sources

- EPSS: 0.51% as of 2026-11-12; percentile 44.24%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-646

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/rails/rails/security/advisories/GHSA-v924-7rp8-4mxh (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/rails/rails/commit/72136ff39153bc8d63ecbc899993848eb3d6573e (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/rails/rails/commit/8106938fb0a595f11006dd1497cd409e27d7d636 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/rails/rails/releases/tag/v8.0.5.2 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/rails/rails/releases/tag/v8.1.4.1 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/rails/rails/commit/72136ff39153bc8d63ecbc899993848eb3d6573e (security-advisories@github.com)

- https://github.com/rails/rails/commit/8106938fb0a595f11006dd1497cd409e27d7d636 (security-advisories@github.com)

- https://github.com/rails/rails/releases/tag/v8.0.5.2 (security-advisories@github.com)

- https://github.com/rails/rails/releases/tag/v8.1.4.1 (security-advisories@github.com)

- https://github.com/rails/rails/security/advisories/GHSA-v924-7rp8-4mxh (security-advisories@github.com)

- https://github.com/advisories/GHSA-v924-7rp8-4mxh (OSV / GitHub Security Advisories; advisory)

- https://osv.dev/vulnerability/GHSA-v924-7rp8-4mxh (OSV / GitHub Security Advisories; osv)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-126186; retrieved 2026-11-12; source updated 2026-11-12

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-126186; retrieved 2026-11-11; source updated 2026-11-10

- OSV / GitHub Security Advisories: https://osv.dev/vulnerability/GHSA-v924-7rp8-4mxh; retrieved 2026-11-10; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-126186; retrieved 2026-11-12; source updated Not reported

Revision: 6090def0be0d115a306dfb00446b41514966d9e38ed6313237a8c15c96ddb695

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