CVE-2026-126186

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-126186", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-11-10T20:07:44.956Z", "datePublished": "2026-11-10T21:14:22.083Z", "dateUpdated": "2026-11-12T18:01:13.625Z"}, "containers": {"cna": {"title": "Active Storage: Possible arbitrary file read and remote code execution in Active Storage video previews, analysis and image processing", "problemTypes": [{"descriptions": [{"cweId": "CWE-646", "lang": "en", "description": "CWE-646: Reliance on File Name or Extension of Externally-Supplied File", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}}], "references": [{"name": "https://github.com/rails/rails/security/advisories/GHSA-v924-7rp8-4mxh", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/rails/rails/security/advisories/GHSA-v924-7rp8-4mxh"}, {"name": "https://github.com/rails/rails/commit/72136ff39153bc8d63ecbc899993848eb3d6573e", "tags": ["x_refsource_MISC"], "url": "https://github.com/rails/rails/commit/72136ff39153bc8d63ecbc899993848eb3d6573e"}, {"name": "https://github.com/rails/rails/commit/8106938fb0a595f11006dd1497cd409e27d7d636", "tags": ["x_refsource_MISC"], "url": "https://github.com/rails/rails/commit/8106938fb0a595f11006dd1497cd409e27d7d636"}, {"name": "https://github.com/rails/rails/releases/tag/v8.0.5.2", "tags": ["x_refsource_MISC"], "url": "https://github.com/rails/rails/releases/tag/v8.0.5.2"}, {"name": "https://github.com/rails/rails/releases/tag/v8.1.4.1", "tags": ["x_refsource_MISC"], "url": "https://github.com/rails/rails/releases/tag/v8.1.4.1"}], "affected": [{"vendor": "rails", "product": "rails", "versions": [{"version": ">= 8.1, < 8.1.4.1", "status": "affected"}, {"version": "< 8.0.5.2", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-11-10T21:14:22.083Z"}, "descriptions": [{"lang": "en", "value": "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."}], "source": {"advisory": "GHSA-v924-7rp8-4mxh", "discovery": "UNKNOWN"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-11-12T16:30:58.504398Z", "id": "CVE-2026-126186", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-11-12T18:01:13.625Z"}}]}}

{}

{"affected": [{"affectedData": [{"product": "rails", "vendor": "rails", "versions": [{"status": "affected", "version": ">= 8.1, < 8.1.4.1"}, {"status": "affected", "version": "< 8.0.5.2"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "id": "CVE-2026-126186", "lastModified": "2026-11-12T22:09:39.233", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 5.9, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-126186", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-11-12T16:30:58.504398Z", "version": "2.0.3"}}]}, "published": "2026-11-10T22:18:31.843", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/rails/rails/commit/72136ff39153bc8d63ecbc899993848eb3d6573e"}, {"source": "security-advisories@github.com", "url": "https://github.com/rails/rails/commit/8106938fb0a595f11006dd1497cd409e27d7d636"}, {"source": "security-advisories@github.com", "url": "https://github.com/rails/rails/releases/tag/v8.0.5.2"}, {"source": "security-advisories@github.com", "url": "https://github.com/rails/rails/releases/tag/v8.1.4.1"}, {"source": "security-advisories@github.com", "url": "https://github.com/rails/rails/security/advisories/GHSA-v924-7rp8-4mxh"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-646"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{"bugzilla": {"description": "activestorage: Active Storage: Remote code execution via unsafe file extension handling in media processing", "id": "2571283", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2571283"}, "csaw": false, "cvss3": {"cvss3_base_score": "8.8", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-641", "details": ["A flaw was found in Active Storage. When handling uploaded media attachments, Active Storage retains user-supplied file extensions on temporary files passed to external processing tools such as FFmpeg and ImageMagick. A remote attacker can exploit this issue by uploading a crafted file with a specific extension and content type, forcing the external utilities to select unintended decoders. Under certain system configurations, this flaw can result in arbitrary file disclosure or remote code execution."], "mitigation": {"lang": "en:us", "value": "Disable automated media analysis and preview generation for untrusted uploaded attachments in the application configuration.\nIn the Rails application configuration (for example, in `config/application.rb` or the relevant environment file under `config/environments/`), remove the FFmpeg previewer and analyzers:\n```ruby\nconfig.active_storage.previewers.delete(ActiveStorage::Previewer::VideoPreviewer)\nconfig.active_storage.analyzers.delete(ActiveStorage::Analyzer::VideoAnalyzer)\nconfig.active_storage.analyzers.delete(ActiveStorage::Analyzer::AudioAnalyzer)\n```\nAdditionally, ensure that image processing does not delegate to unsafe ImageMagick decoders, or switch the variant processor to `:vips`.\nCaveats: Disabling these analyzers and previewers stops automatic metadata extraction (such as audio and video duration) and prevents preview thumbnail generation for uploaded multimedia files. Application services must be restarted for these configuration changes to take effect."}, "name": "CVE-2026-126186", "package_state": [{"cpe": "cpe:/a:redhat:3scale:2.13", "fix_state": "Affected", "package_name": "3scale-amp2/system-rhel8", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:3scale:2.13", "fix_state": "Affected", "package_name": "3scale-amp2/system-rhel9", "product_name": "Red Hat 3scale API Management Platform 2"}, {"cpe": "cpe:/a:redhat:3scale:2.13", "fix_state": "Affected", "package_name": "3scale-amp2/zync-rhel9", "product_name": "Red Hat 3scale API Management Platform 2"}], "public_date": "2026-11-10T21:14:22Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-126186\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-126186\nhttps://github.com/rails/rails/commit/72136ff39153bc8d63ecbc899993848eb3d6573e\nhttps://github.com/rails/rails/commit/8106938fb0a595f11006dd1497cd409e27d7d636\nhttps://github.com/rails/rails/releases/tag/v8.0.5.2\nhttps://github.com/rails/rails/releases/tag/v8.1.4.1\nhttps://github.com/rails/rails/security/advisories/GHSA-v924-7rp8-4mxh"], "statement": "This vulnerability is rated as having an Important severity because it allows remote authenticated users to potentially achieve arbitrary file disclosure or code execution within the application context without requiring privileged access. Applications are exposed when they accept uploads from untrusted sources and utilize Active Storage to analyze or preview media files using external binaries such as FFmpeg or ImageMagick. While full remote code execution via AviSynth scripts is constrained on standard enterprise Linux distributions that omit AviSynth build options, alternative decoder delegation paths may still expose sensitive local application data.", "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[8.1,8.1.4.1)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[0,8.0.5.2)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "rails", "source": "cna", "vendor": "rails"}, "product": "rails", "vendor": "rails"}], "created": "2026-11-12T01:00:09.863058+00:00", "updated": "2026-11-13T11:15:09.179004+00:00", "vendors": ["rails", "rails$PRODUCT$rails"]}