CVE-2025-40636 Overview
CVE-2025-40636 is a SQL injection vulnerability in the Joomla module mod_vvisit_counter version 2.0.4j3. The flaw resides in the handling of the cip_vvisitcounter cookie, which the module reads on every page where it tracks visits. Unauthenticated attackers can inject arbitrary SQL statements through this cookie and retrieve database contents. The vulnerability is classified under CWE-89 (Improper Neutralization of Special Elements used in an SQL Command).
Critical Impact
Remote, unauthenticated attackers can extract arbitrary database content from any Joomla site running the affected module by manipulating a cookie value.
Affected Products
- Joomla CMS extension mod_vvisit_counter
- Version 2.0.4j3
- Any Joomla site embedding the module on visitor-tracked endpoints
Discovery Timeline
- 2025-10-03 - CVE-2025-40636 published to NVD
- 2026-04-15 - Last updated in NVD database
Technical Details for CVE-2025-40636
Vulnerability Analysis
The mod_vvisit_counter module tracks unique visitors using a client-supplied cookie named cip_vvisitcounter. The module passes the cookie value into a SQL query without proper sanitization or parameterization. An attacker can supply a crafted cookie value that breaks out of the intended query context and appends arbitrary SQL.
Because visit counting executes on every page where the module is rendered, the injection point is reachable on the public-facing front end. No authentication, user interaction, or special privileges are required. The vulnerability scores 9.3 under CVSS 4.0 due to network reach and high impact on confidentiality, integrity, and availability of the backing database.
The EPSS score for this issue is 0.036% (10.8th percentile), reflecting limited public exploit activity at the time of analysis, though the technical barrier to exploitation is low.
Root Cause
The module concatenates the raw cip_vvisitcounter cookie value directly into a SQL statement issued against the Joomla database. The code path neither uses prepared statements nor applies the Joomla database driver's quoting and escaping APIs. Any string accepted by the HTTP cookie parser flows into the query unchanged.
Attack Vector
An attacker sends an HTTP request to any Joomla page that renders the visitor counter and includes a malicious Cookie: cip_vvisitcounter=<payload> header. The payload terminates the original SQL literal and appends statements such as UNION SELECT clauses to exfiltrate data, including Joomla user records, session tokens, and configuration secrets. Blind, time-based, and union-based SQLi techniques are all viable against the unsanitized input.
No proof-of-concept exploit is publicly catalogued for this CVE. Refer to the INCIBE Security Notice for additional technical context.
Detection Methods for CVE-2025-40636
Indicators of Compromise
- HTTP requests containing SQL metacharacters (', ", --, UNION, SELECT, SLEEP) inside the cip_vvisitcounter cookie value
- Unusually long or URL-encoded cip_vvisitcounter cookie values inconsistent with normal IP-formatted tokens
- Joomla database error messages or stack traces referencing the visit counter module in web server logs
- Outbound connections or DNS queries originating from the database host shortly after suspicious cookie traffic
Detection Strategies
- Inspect web access logs for cookie values that deviate from the expected IP address format used by mod_vvisit_counter
- Deploy web application firewall (WAF) rules that flag SQL injection patterns within HTTP cookie headers, not just query strings and POST bodies
- Correlate spikes in 500-series responses on Joomla pages with anomalous cookie payloads
- Review database query logs for SELECT statements that reference the visit counter table with embedded boolean or UNION clauses
Monitoring Recommendations
- Enable verbose logging on the Joomla front-end web server and forward logs to a centralized analytics platform
- Alert on repeated requests from a single source that vary the cip_vvisitcounter cookie across requests
- Track database response times for visit counter queries to surface time-based blind SQLi attempts
How to Mitigate CVE-2025-40636
Immediate Actions Required
- Disable or unpublish the mod_vvisit_counter module in the Joomla administrator interface until a fixed version is confirmed
- Block or filter the cip_vvisitcounter cookie at the reverse proxy or WAF layer when its value contains non-IP characters
- Rotate Joomla administrator credentials, API tokens, and database passwords if exploitation is suspected
- Audit the Joomla #__users table and recent session activity for unauthorized access
Patch Information
No vendor patch is referenced in the NVD entry for CVE-2025-40636. Administrators should monitor the INCIBE Security Notice and the module's distribution channel for an updated release. Until a verified fix exists, treat the module as unsafe to run in production.
Workarounds
- Replace mod_vvisit_counter with an actively maintained visitor analytics solution that uses parameterized queries
- Add a WAF signature that rejects requests where cip_vvisitcounter fails strict IPv4 or IPv6 validation
- Apply database least-privilege so the Joomla application account cannot read sensitive tables outside its scope
# Example ModSecurity rule to drop malformed cip_vvisitcounter cookies
SecRule REQUEST_COOKIES:cip_vvisitcounter "!@rx ^[0-9a-fA-F:.]{1,45}$" \
"id:1004001,phase:1,deny,status:403,log,\
msg:'CVE-2025-40636: invalid cip_vvisitcounter cookie format'"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
