CVE-2026-126186

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.

• CWE-646

• https://github.com/rails/rails/commit/72136ff39153bc8d63ecbc899993848eb3d6573e
• https://github.com/rails/rails/commit/8106938fb0a595f11006dd1497cd409e27d7d636
• https://github.com/rails/rails/releases/tag/v8.0.5.2
• https://github.com/rails/rails/releases/tag/v8.1.4.1
• https://github.com/rails/rails/security/advisories/GHSA-v924-7rp8-4mxh

Published

Nov 10, 2026

Last Modified

Nov 12, 2026

Status

Awaiting Analysis

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-126180A improper neutralization of special elements used in a temp…8.4
• CVE-2026-126181A use of hard-coded credentials vulnerability in Fortinet Fo…8
• CVE-2026-126182A improper control of generation of code ('code injection') …7.2
• CVE-2026-126183A authorization bypass through user-controlled key vulnerabi…8.7
• CVE-2026-126184A authentication bypass by spoofing vulnerability in Fortine…8.2
• CVE-2026-126185A improper control of generation of code ('code injection') …7.2
• CVE-2026-126187React is a JavaScript library for building user interfaces. …9.5
• CVE-2026-126188Active Storage makes it simple to upload and reference files…3.7
• CVE-2026-126189Soup Sieve is a CSS selector library designed to be used wit…5.3
• CVE-2026-12619Improper Neutralization of Input During Web Page Generation …5.4
• CVE-2026-126190Soup Sieve is a CSS selector library designed to be used wit…7.5
• CVE-2026-126191Soup Sieve is a CSS selector library designed to be used wit…7.5