CVE-2026-4776: Mautic API SQL Injection – Authenticated Data Exfiltration Risk

Technical summary

CVE-2026-4776 is an SQL injection vulnerability (CWE-89) residing in Mautic's API contact filtering endpoint. The root cause is insufficient recursive sanitization of nested query parameters. Standard input validation routines fail to properly handle deeply nested or layered query structures, allowing an authenticated API consumer to bypass filtering controls and inject arbitrary SQL. The CVSS 3.1 score of 7.1 (HIGH) reflects high confidentiality impact, low integrity risk, and limited availability impact, constrained by the requirement for prior authentication (PR:L) and network-only attack surface (AV:N/AC:L).

Business impact

A compromised or malicious API user could extract sensitive contact data, campaign information, or other marketing records from the Mautic instance without authorization. While data modification is not the primary risk, query-based denial-of-service through resource-intensive injected SQL could degrade system performance or availability. For organizations using Mautic to manage customer contact databases, data exfiltration represents a material compliance and reputation risk. The authenticated nature of the attack limits blast radius but increases insider-threat and API key compromise scenarios.

Affected systems

This vulnerability affects Mautic instances with exposed API endpoints accessible to authenticated users. The precise affected version range is not detailed in vendor advisories reviewed; organizations should verify their Mautic deployment version against official vendor guidance. Instances where API keys or credentials are shared across teams, integrated with third-party tools, or stored in version control are at heightened risk of unauthorized access by bad actors.

Exploitability

Exploitation requires valid API credentials—the attacker cannot exploit this remotely without prior authentication. The attack complexity is low once credentials are obtained, and no user interaction is needed. An attacker with stolen or mismanaged API keys, or an insider with legitimate access, can weaponize this with minimal effort. The vulnerability is not currently tracked in the CISA Known Exploited Vulnerabilities catalog, but the straightforward nature of SQL injection post-authentication suggests practical exploit code could be developed quickly.

Remediation

Mautic has released security updates addressing this vulnerability through improved recursive sanitization of query parameters. Organizations must apply the vendor-provided patch to all Mautic instances with exposed APIs. Parallel to patching, implement strict API key lifecycle management: rotate credentials, restrict API scopes to minimum required permissions, enforce API rate limiting, and monitor API logs for anomalous query patterns. Consider network-level controls such as IP whitelisting for API access.

Patch guidance

Consult the official Mautic security advisory for the specific patched version. Apply patches in a phased approach: test in a staging environment first to verify compatibility with custom plugins or integrations, then deploy to production instances. Verify patch application by confirming the presence of updated input validation routines in the contact filtering endpoint. Implement a post-patch audit of recent API activity logs to detect whether the vulnerability was exploited prior to remediation.

Detection guidance

Monitor API access logs for suspicious contact filter queries, particularly those containing SQL keywords (UNION, SELECT, DROP, INSERT, etc.) within nested parameter structures. Implement Web Application Firewall (WAF) rules to detect SQL injection signatures in API requests targeting the contact filter endpoint. Use database query auditing to identify anomalous SELECT statements originating from the Mautic application service account. Correlate API key usage patterns with known user behavior to identify compromised credentials.

Why prioritize this

Although the vulnerability requires prior authentication, its combination of high confidentiality impact, ease of exploitation post-authentication, and potential for broad data exfiltration warrants timely remediation. Organizations managing customer data through Mautic should prioritize patching to prevent unauthorized access that could trigger breach disclosure obligations. The vulnerability is not yet widely exploited in the wild, offering a narrow window for proactive patching before adversaries operationalize it.

Risk score, explained

The CVSS 3.1 score of 7.1 reflects a HIGH severity assessment driven by high confidentiality impact (the primary concern), network accessibility, and low attack complexity post-authentication. The score is tempered by the mandatory authentication requirement (PR:L) and limited integrity and availability impact. For organizations with strict API security practices and strong credential management, practical risk may be lower; for those with credential sprawl or overly permissive API scopes, actual risk may exceed the base score.

Frequently asked questions