Arbitrary File Upload Affecting @payloadcms/storage-s3 package, versions <3.90.0>=4.0.0-canary.0 <4.0.0-canary.34
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published8 Oct 2026
- disclosed7 Oct 2026
- creditUnknown
Introduced: 7 Oct 2026
NewCVE-2026-105868 (opens in a new tab)How to fix?
Upgrade @payloadcms/storage-s3 to version 3.90.0, 4.0.0-canary.34 or higher.
Overview
@payloadcms/storage-s3 is a Payload storage adapter for Amazon S3
Affected versions of this package are vulnerable to Arbitrary File Upload via insufficient validation of upload identity and MIME type in the upload handling pipeline, specifically in generateFileData and related file-type detection logic. An authenticated attacker can upload a file with a manipulated MIME type or filename that misrepresents its true content type - for example, delivering XML or SVG content under a non-XML MIME type - causing the server to serve the file without the appropriate Content-Security-Policy restrictions. This allows the attacker to execute scripts in the context of a victim user's browser when the file is subsequently accessed.