CVE-2026-96365 in Webform
Summary
by MITRE • 10/23/2026
Allocation of Resources Without Limits or Throttling vulnerability in Drupal Webform allows Excessive Allocation. This issue affects Webform versions: from 0.0.0 to 6.2.12, from 6.3.0 to 6.3.1.
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Analysis
by VulDB Data Team • 10/23/2026
The identified vulnerability represents a classic instance of resource exhaustion caused by the absence of adequate input validation and rate limiting mechanisms within the Drupal Webform module. This flaw allows an attacker or even a legitimate user with malicious intent to trigger actions that consume disproportionate amounts of server resources, such as CPU cycles, memory, or database connections. By exploiting this lack of throttling, it is possible to degrade the performance of the entire web application or render it completely unavailable to other users, effectively achieving a denial-of-service condition against the targeted Drupal instance. The vulnerability stems from the system's failure to enforce limits on how many times certain operations can be executed within a specific timeframe or without proper resource accounting for each request processed by the form submission logic.
From a technical perspective, this issue aligns with CWE-400, which describes conditions where resources are not properly limited during allocation, leading to exhaustion of those resources. In the context of Drupal Webform versions ranging from 0.0.0 through 6.2.12 and 6.3.0 through 6.3.1, the application likely processes form submissions without implementing sufficient checks on the volume or complexity of data being submitted. This could involve allowing excessively large file uploads, triggering complex recursive calculations during validation, or initiating multiple database transactions in rapid succession without any cap. The lack of throttling means that a single actor can saturate server resources by sending a high frequency of requests or submitting forms with payloads designed to maximize processing time and memory usage.
The operational impact of this vulnerability is significant for organizations relying on Drupal Webform for data collection, customer interactions, or internal workflows. A successful exploitation could lead to service degradation where legitimate users experience slow load times or timeouts due to resource contention. In more severe scenarios, the server may crash entirely, requiring a restart and resulting in extended downtime. This not only disrupts business operations but also poses a security risk as it can mask other malicious activities occurring simultaneously on the compromised system. Furthermore, if the application is part of a larger infrastructure behind load balancers or CDNs, excessive resource consumption by one node could trigger automatic scaling events that incur unnecessary costs or cause cascading failures across the cluster.
To mitigate this vulnerability, immediate action should be taken to upgrade the Drupal Webform module to a version beyond 6.2.12 and 6.3.1 where these limits have been addressed. Administrators must ensure they are running patched versions that include proper resource management controls. In addition to upgrading, implementing web application firewall rules can help mitigate the risk by rate-limiting requests from specific IP addresses or user agents that exhibit suspicious behavior patterns indicative of abuse. Monitoring server metrics such as memory usage and CPU load in real-time allows for early detection of abnormal spikes that might indicate an ongoing exploitation attempt. It is also advisable to review form configurations to disable unnecessary features like large file uploads if they are not required, thereby reducing the attack surface available for resource exhaustion attacks.
This vulnerability maps directly to MITRE ATT&CK technique T1496, which involves Resource Hijacking or Denial of Service through environmental hijacking. By exhausting system resources, an attacker can effectively deny service to legitimate users without necessarily compromising data confidentiality or integrity in the traditional sense. The focus remains on availability as a core component of the CIA triad being compromised. Organizations should treat this with high priority due to its simplicity and effectiveness against unpatched systems. Regular security audits that include stress testing and load testing can help identify similar weaknesses before they are exploited by malicious actors. Ensuring that all third-party modules like Webform are kept up-to-date is a critical component of maintaining the overall health and resilience of a Drupal-based web application infrastructure.