Summary
CVE-2026-54836 is a critical, unauthenticated SQL Injection vulnerability (CWE-89) in the YMC Filter WordPress plugin (slug: ymc-smart-filter), affecting all versions up to and including 3.11.5. It carries a CVSS 3.1 score of 9.3 (Critical), is exploitable over the network with no authentication or user interaction required, and is capable of extracting database contents beyond the plugin’s own data scope due to a confirmed Scope Change in the CVSS vector.
Technical details
- Root cause: Improper neutralization of special elements used in SQL commands (CWE-89) within the plugin’s search functionality. Attacker-controlled input is incorporated into database queries without proper sanitization or parameterization, enabling arbitrary SQL to be injected and executed against the WordPress database.
- Trigger conditions: An unauthenticated attacker sends a crafted HTTP/HTTPS request to the plugin’s search or filter endpoint. No credentials, privileged access, or victim interaction are required to trigger the vulnerability.
- Attack vector: Network (AV:N) — the vulnerability is directly reachable over the internet via standard HTTP/HTTPS requests to any WordPress site running a vulnerable version of the plugin.
- Impact: High confidentiality impact with Scope Change (C:H / S:C), meaning successful exploitation can expose database contents beyond the plugin’s own data boundary — including WordPress user credentials, password hashes, PII, session tokens, and other sensitive content stored in the database. A limited availability impact (A:L) is also present.
Affected software
- YMC Filter (WordPress plugin slug:
ymc-smart-filter), versions n/a through 3.11.5 (inclusive)
Severity
- CVSS v3.1 Base Score: 9.3 (Critical)
- Vector String:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L
Mitigation and recommended actions
- Immediate: Update the YMC Filter plugin to version 3.11.6 or later. The developer explicitly patched the SQL Injection vulnerability in the search functionality in version 3.11.6, as documented in the official plugin changelog. The latest available version is 3.12.3.
- If immediate patching is not feasible: Deploy a Web Application Firewall (WAF) rule to block or sanitize SQL metacharacter sequences in requests targeting the plugin’s filter and search endpoints. Additionally, consider temporarily deactivating the plugin until patching can be applied.
IONIX Status
The IONIX research team is tracking ongoing exploitation attempts and recommends immediate patching. Potentially affected assets are outlined in this post.

