CVE-2026-80440 Overview
The Hustle WordPress plugin before version 7.8.14.2 contains a shortcode injection vulnerability in its form submission handler. The plugin substitutes user-submitted values into the confirmation message returned after submission without properly stripping shortcode syntax. Its protective guard can be bypassed by nesting shortcodes, allowing unauthenticated attackers to execute any shortcode registered on the target site. This is classified as an improper neutralization of special elements in output [CWE-74] issue.
Critical Impact
Unauthenticated attackers can execute arbitrary shortcodes registered on the WordPress site by submitting crafted values through Hustle forms, potentially exposing sensitive data or triggering unintended plugin functionality.
Affected Products
- Hustle WordPress plugin versions prior to 7.8.14.2
- WordPress sites using Hustle forms with shortcode-enabled response messages
- Any WordPress installation exposing Hustle submission endpoints publicly
Discovery Timeline
- 2026-09-09 - CVE-2026-80440 published to NVD
- 2026-09-09 - Last updated in NVD database
Technical Details for CVE-2026-80440
Vulnerability Analysis
The Hustle plugin returns a confirmation message after a user submits a form. That message can interpolate values the user supplied in the submission. Before echoing the message, the plugin applies a guard intended to strip WordPress shortcodes from the submitted values.
The guard operates on a single pass and does not account for nested shortcode syntax. An attacker can construct payloads where an outer wrapper is stripped but leaves behind valid inner shortcode markup. When WordPress subsequently processes the message through do_shortcode(), the reconstructed shortcode is executed.
Because form submission is available to unauthenticated visitors, no credentials or user interaction beyond a crafted request are required. The impact depends on which shortcodes are registered on the target site, including those exposed by other installed plugins.
Root Cause
The root cause is an insufficient sanitization routine that fails to recursively neutralize shortcode delimiters. The pattern matches only the outermost [shortcode] structure, so payloads such as [[nested]shortcode] collapse to a valid shortcode once the outer layer is removed. This is a classic injection weakness aligned with [CWE-74].
Attack Vector
Exploitation is performed remotely over the network by submitting a crafted value through any Hustle form field that is echoed in the response message. The attacker embeds a nested shortcode payload designed to survive the plugin's stripping routine. Refer to the WPScan Vulnerability Report for full technical details on the payload structure.
Detection Methods for CVE-2026-80440
Indicators of Compromise
- HTTP POST requests to Hustle form submission endpoints containing bracket characters [ and ] inside form field values
- Submission payloads with nested bracket sequences such as [[ or ][ in fields normally accepting plain text
- Unexpected shortcode expansion output visible in server response bodies after form submissions
- Web server access logs showing repeated submissions from a single source with anomalous field content
Detection Strategies
- Inspect WordPress request logs for form submissions containing shortcode delimiters where none are expected
- Correlate Hustle module submission events with output of privileged shortcodes registered by other plugins
- Deploy web application firewall rules that flag nested bracket patterns targeting /wp-admin/admin-ajax.php actions associated with Hustle
Monitoring Recommendations
- Enable verbose logging on the Hustle plugin and forward records to a central analytics platform for review
- Monitor for outbound requests or file changes that follow Hustle form submissions, indicating shortcode side effects
- Alert on version drift for the Hustle plugin across managed WordPress sites to ensure patched releases remain deployed
How to Mitigate CVE-2026-80440
Immediate Actions Required
- Update the Hustle plugin to version 7.8.14.2 or later on every WordPress site in the environment
- Audit the list of shortcodes registered on affected sites and remove or disable any that expose sensitive data or state-changing actions
- Review recent Hustle form submissions for payloads containing bracket characters and investigate any matches
Patch Information
The vendor addressed the vulnerability in Hustle version 7.8.14.2 by strengthening the shortcode-stripping routine to handle nested syntax. Administrators should upgrade through the WordPress plugin dashboard or by deploying the updated package from the official repository. See the WPScan Vulnerability Report for advisory details.
Workarounds
- Temporarily disable the Hustle plugin on internet-facing sites until the patched version is installed
- Restrict access to Hustle form endpoints with a web application firewall rule blocking submissions containing bracket characters
- Unregister high-impact shortcodes from other plugins on sites where the Hustle plugin cannot be updated immediately
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
