CVE-2019-6340 is a remote code execution vulnerability in Drupal Core. CISA added it to the Known Exploited Vulnerabilities catalogue on 25 March 2022, which means attackers have used it in real attacks. In Drupal Core, some field types do not properly sanitize data from non-form sources. This can lead to arbitrary PHP code execution in some cases.
How Drupal Core remote code execution works
CVE-2019-6340 is dangerous because it turns a content handling flaw into code execution inside the Drupal application runtime. When data from non-form sources is not sanitized correctly, an attacker can sometimes push input into paths that the platform later interprets as executable PHP rather than ordinary content.
That distinction matters: a remote code execution issue is not just a broken page or a malformed field. It can let an unauthenticated or low-friction attacker move from web input to server-side execution, which means the compromise target is the application host, not only the Drupal site itself.
Why this vulnerability is high impact
The danger in this class of flaw comes from the trust boundary it crosses. A CMS is expected to treat submitted content as data, but once sanitization fails, the attacker may influence runtime behavior, alter site output, or reach deeper system-level actions depending on how the environment is deployed.
This is also why Drupal core remote code execution belongs in the same practical category as other actively exploited code execution flaws. Real-world exploitation can quickly expand from a single vulnerable endpoint to broader site compromise, especially where the application has access to files, credentials, or internal services. For a broader view of how exploited vulnerabilities are prioritised and tracked, see the NIST National Vulnerability Database and the CVE Program.
How organisations check exposure and reduce blast radius
Exposure checks should start with asset inventory, because the practical question is whether any Drupal Core instance is present and reachable in a way that could be abused before remediation lands. Internet-facing deployments deserve the most urgent review, but internal-only systems still matter if they can be reached through VPNs, admin portals, or laterally from other compromised assets.
Vendor advisories and authoritative vulnerability records should drive version-specific decisions, not guesswork or blog summaries. Until the vulnerable systems are confirmed and fixed, compensating controls such as reducing exposure, tightening administrative access, and watching for suspicious web requests can limit the chance that the flaw becomes a full compromise.
Detection, recovery, and post-exploitation review
Because this is a code execution issue, detection should not stop at patching. Teams should review web server logs, application logs, file integrity changes, unexpected PHP files, new scheduled tasks, and unusual outbound connections that suggest a foothold or post-exploitation activity.
If exploitation is suspected, treat the incident as a possible full application compromise rather than a narrow vulnerability event. The attacker may have used the initial execution path to plant persistence, change application logic, or harvest anything the Drupal process could reach. In that situation, compromise review should include the web root, adjacent configuration files, and any secrets or service credentials the application could expose.
Risk and Threat Considerations
The main risk is that a content-layer sanitization bug can become server-side execution with very little user interaction. Once that happens, the attacker may be able to alter the site, steal data, pivot to nearby systems, or use the host as an entry point for broader compromise.
Failure mechanism: The application misclassifies attacker-controlled input as trusted content, allowing code execution through a path that should only process data.
Impact: A successful exploit can lead to site takeover, data theft, persistence, or downstream access to other systems and credentials reachable from the Drupal host.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
NIST SP 800-53 Rev 5 and CIS Controls v8 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-53 Rev 5 | SI-2 — Flaw Remediation | RCE vulnerabilities require timely flaw remediation and verification. |
| SI-4 — System Monitoring | Post-exploitation review depends on monitoring logs and anomalous web activity. | |
| SC-7 — Boundary Protection | Internet exposure strongly affects the exploitability of a remote code execution flaw. | |
| Recommendation — Prioritise SI-2 to track, patch, and verify remotely exploitable flaws on exposed Drupal systems. Apply SI-4 to detect suspicious requests, file changes, and outbound activity after exploitation. Use SC-7 to reduce direct exposure of vulnerable Drupal instances until remediation is complete. | ||
| CIS Controls v8 | CIS-7 — Continuous Vulnerability Management | Actively exploited CVEs require inventory, prioritisation, and remediation workflows. |
| CIS-10 — Malware Defenses | Code execution incidents often require endpoint and host hardening to detect persistence. | |
| Recommendation — Use CIS-7 to inventory Drupal assets, prioritise exposure, and close remediation gaps quickly. Use CIS-10 to look for malicious files, persistence, and post-exploit tooling on compromised hosts. | ||
Practitioner Guidance
Why practitioners should care: For Drupal Core vulnerabilities of this kind, the priority is not just applying a fix, but confirming whether the site was exposed long enough for exploitation to occur. In practice, the question is whether the system needs both remediation and compromise investigation.
What to watch for: Focus on any sign that the web tier changed unexpectedly after the vulnerable window, especially new files, altered templates, suspicious PHP execution, or unusual authentication and outbound activity. If the system was internet-facing, assume attacker interest was plausible and validate the host state accordingly.
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Reviewed and updated by the NHIMG editorial team on October 17, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org