CVE-2026-17509 Overview
CVE-2026-17509 is a time-based SQL injection vulnerability in the WPML Multilingual CMS plugin for WordPress. The flaw affects all versions up to and including 4.9.5. Attackers exploit the elementIds parameter, which lacks proper escaping and query preparation. An authorization bypass compounds the issue: the registered authorization callback fails to execute, so any authenticated user can reach administrative translation functionality regardless of role. Subscriber-level accounts and above can inject SQL to extract sensitive database contents. The vulnerability is categorized under [CWE-89] (Improper Neutralization of Special Elements used in an SQL Command).
Critical Impact
Authenticated attackers with Subscriber-level access can extract sensitive database contents through time-based SQL injection in the elementIds parameter.
Affected Products
- WPML Multilingual CMS plugin for WordPress
- All versions up to and including 4.9.5
- WordPress sites with translation management functionality exposed
Discovery Timeline
- 2026-09-08 - CVE-2026-17509 published to NVD
- 2026-09-08 - Last updated in NVD database
Technical Details for CVE-2026-17509
Vulnerability Analysis
The vulnerability chains two distinct weaknesses. First, an authorization bypass exposes administrative translation endpoints to any authenticated user. Second, those endpoints pass the elementIds parameter into an SQL query without sufficient escaping or prepared statement usage. The result is time-based blind SQL injection reachable by low-privileged accounts.
Time-based injection allows attackers to infer query results by observing response delays introduced through functions such as SLEEP(). Over repeated requests, adversaries reconstruct arbitrary data from the WordPress database, including wp_users credentials and session tokens.
Root Cause
Two defects combine to enable exploitation. The elementIds parameter is concatenated into an SQL statement without escaping or parameter binding, violating safe query construction practices. Separately, the AJAX endpoint registers an authorization callback that does not execute as intended, so role checks intended to restrict access to administrators or translators never enforce.
Attack Vector
Exploitation requires an authenticated WordPress account at Subscriber level or higher. Subscriber registration is enabled by default on many WordPress deployments, lowering the barrier to entry. The attacker submits a crafted request to the vulnerable WPML translation endpoint with a malicious elementIds payload. The payload appends a time-delay SQL clause to the existing query, allowing boolean inference of database contents through response timing.
The vulnerability manifests in the WPML translation management AJAX handler. See the Wordfence Vulnerability Analysis for technical details on the affected code path.
Detection Methods for CVE-2026-17509
Indicators of Compromise
- Repeated POST requests to WPML AJAX endpoints from Subscriber-level accounts containing unusually long response times.
- Request bodies with elementIds parameters containing SQL keywords such as SLEEP, BENCHMARK, UNION, or SELECT.
- Sudden increases in database CPU utilization correlated with WordPress AJAX traffic.
- New or dormant Subscriber accounts making requests to administrative translation endpoints.
Detection Strategies
- Deploy web application firewall rules that inspect the elementIds parameter for SQL metacharacters and time-delay functions.
- Monitor WordPress admin-ajax.php requests correlated with WPML actions for anomalous parameter content and response latency.
- Enable MySQL query logging or performance schema monitoring to identify queries containing SLEEP() or unusual UNION structures.
Monitoring Recommendations
- Audit accounts with Subscriber role or higher for unexpected activity against translation endpoints.
- Alert on any WPML AJAX request producing response times exceeding a defined baseline threshold.
- Track authentication events for newly registered accounts that immediately access WPML functionality.
How to Mitigate CVE-2026-17509
Immediate Actions Required
- Update WPML Multilingual CMS to a version later than 4.9.5 once the vendor publishes a fix. Review the WPML Changelog for release details.
- Disable open user registration on WordPress sites that do not require it to reduce the pool of accounts eligible to exploit this flaw.
- Audit existing Subscriber-level accounts and remove any that are unused or suspicious.
Patch Information
The vendor tracks fixes in the WPML Changelog. Administrators should apply the patched release addressing versions through 4.9.5 as soon as it becomes available. Confirm the corrective release resolves both the SQL injection in elementIds and the authorization callback bypass.
Workarounds
- Restrict access to admin-ajax.php WPML actions through web application firewall rules limited to trusted administrator IP ranges.
- Temporarily deactivate the WPML plugin on non-critical sites until an official patch is applied.
- Enforce strong password and multi-factor authentication requirements on all WordPress accounts to reduce credential-based access to Subscriber roles.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
