Authenticated arbitrary file upload via MIME trust
Published Jul 8, 2026 · Updated Jul 8, 2026
Unrestricted file upload in Grav API plugin 1.0.0 allows remote authenticated users to store arbitrary content through the avatar endpoint. UsersController trusts getClientMediaType(), accepts any image/* declaration, and moves the uninspected body into user/accounts/avatars/ under a predictable name. Any account with site.login can write PHP, SVG, or polyglot files, but direct HTTP access remains blocked unless another flaw or server misconfiguration exposes them.
Summary
What happened
Unrestricted file upload in Grav API plugin 1.0.0 allows remote authenticated users to store arbitrary content through the avatar endpoint. UsersController trusts getClientMediaType(), accepts any image/* declaration, and moves the uninspected body into user/accounts/avatars/ under a predictable name. Any account with site.login can write PHP, SVG, or polyglot files, but direct HTTP access remains blocked unless another flaw or server misconfiguration exposes them.
The record
- CVE
- CVE-2026-58654
- Published
- Jul 8, 2026
- Updated
- Jul 8, 2026
- Vendor
- Grav
- Product
- Grav
- Classifications
- CWE-434, T1105
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 8, 2026CVE publishedPublication date reported by the CVE source.
- Jul 8, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <1.0.1
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Vendor advisory avatar upload proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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