CVE-2026-126084

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, when a GCS service is configured with the cache_control option, ActiveStorage::Service::GCSService#url_for_direct_upload signs direct-upload URLs with V4, and the V4 signature covers only the Cache-Control and Host headers. A direct-upload client can therefore send a Content-Type of its choosing, and can omit the declared Content-MD5, without invalidating the URL. GCS stores the supplied content type as object metadata, which takes precedence over the response-content-type that Active Storage sets on download URLs, so an uploaded object could be served as inline HTML under the application's bucket path on storage.googleapis.com. Script in such an object runs on the storage origin rather than the application's, but could register a Service Worker scoped to the bucket path and read or replace a victim's later responses for signed URLs in that bucket. Applications that use the GCS service with cache_control configured and accept direct uploads are affected. GCS services without cache_control sign with V2 and are not affected. This issue is fixed in versions 8.1.4.1 and 8.0.5.2.

• CWE-345

• https://github.com/rails/rails/commit/8d93f6a872e9550a91bf0e4fce50083a235ef3b1
• https://github.com/rails/rails/commit/ddc08ba61a8001e7402864c62e466cf732fc7614
• 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-3w93-6hmw-whh4

Published

Nov 10, 2026

Last Modified

Nov 12, 2026

Status

Awaiting Analysis

• Same Subject, Wrong User: A Cross-Issuer Account Takeover in n8nStrix found an identity-binding bug in n8n's token-exchange flow enabling account takeover.
• 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-2026-126078Action View is a framework for handling view template lookup…6.1
• CVE-2026-126079Action View is a framework for handling view template lookup…6.1
• CVE-2026-126080Active Support is a collection of utility classes and standa…7.5
• CVE-2026-126081Action Pack is a framework for handling and responding to we…7.5
• CVE-2026-126082Rejected reason: This CVE is a duplicate of another CVE.
• CVE-2026-126083Action Pack is a framework for handling and responding to we…7.4
• CVE-2026-126085Active Storage makes it simple to upload and reference files…5.3
• CVE-2026-126087Untrusted search path in the cross-user process launcher in …8.8
• CVE-2026-12609In Eclipse Theia versions 1.66.0 and up until including 1.73…7.5
• CVE-2026-1261The MetForm Pro plugin for WordPress is vulnerable to Stored…7.2
• CVE-2026-12610A flaw was found in sssd. When authenticating with a YubiKey…6.4
• CVE-2026-12611A client may issue HTTP/2 requests to a Jetty server that re…8.7