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Critical Rails Vulnerability Allows File Manipulation via ImageMagick Uploads

Critical Rails Vulnerability Allows File Manipulation via ImageMagick Uploads

First seen 4 Nov 2026, 15:16 UTC • •
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ThreatCluster AI
ThreatCluster •November 4, 2026 at 23:51 UTC
  • •A critical vulnerability in Rails allows unauthenticated file writes via ImageMagick uploads.
  • •Versions 8.0.5.2 and 8.1.4.1 released on November 4, 2026, to address this flaw.
  • •Attackers can read sensitive files, risking remote code execution and lateral movement.

A critical vulnerability in Ruby on Rails (tracked as GHSA-f3w6-w445-fwh9) was disclosed, allowing unauthenticated attackers to write arbitrary files on servers using ImageMagick for file uploads. This flaw affects versions 8.0.5.2 and 8.1.4.1, which were released on November 4, 2026, to patch the issue. The vulnerability arises from Active Storage's handling of file uploads, where certain crafted image files can exploit the lack of restrictions on ImageMagick's coders. Attackers can not only write files but also read sensitive information like secret keys and credentials, potentially leading to remote code execution or lateral movement within systems. Rails has urged users to upgrade immediately, especially since security support for the 8.0 series ends on November 7, 2026. No CVE ID has been assigned yet, and the flaw was reported by a researcher through HackerOne. Previous vulnerabilities in Active Storage were patched in July 2026, but this new issue specifically impacts apps using ImageMagick.

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Timeline

2026-11-04
Rails releases security updates
Versions 8.0.5.2 and 8.1.4.1 released to fix 21 vulnerabilities, including a critical file write flaw.
Dev.To
2026-11-04
Critical vulnerability disclosed
Rails advisory reveals a critical flaw allowing file manipulation via ImageMagick uploads, affecting specific versions.
Thehackernews
2026-11-04
Security support deadline approaching
Rails 8.0 series security support ends on November 7, 2026, urging users to upgrade.
rubyonrails.org

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Common questions

Which Rails versions are affected?
Rails versions 8.0.5.2 and 8.1.4.1 are affected, particularly those using ImageMagick for file uploads.
What should I do to protect my application?
Upgrade to Rails versions 8.0.5.2 or 8.1.4.1 immediately to mitigate the risk.
Is there evidence of active exploitation?
No confirmed exploitation has been reported as of now, but the vulnerability is critical.