CVE-2026-116132 in HTTP::Body
Summary
by MITRE • 10/28/2026
HTTP::Body versions before 1.23_01 for Perl leave the temporary file of an incomplete multipart upload on disk.
The multipart parser creates a temporary file as soon as a file part starts, but adds it to the upload list only when the part completes. Uploads are only ever deleted from that list, by the cleanup option or by the caller, so a body that ends inside a file part leaves its temporary file where nothing can find it.
A remote attacker can fill the temporary directory by repeating such requests, leaving one file behind for each.
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Analysis
by VulDB Data Team • 10/28/2026
The vulnerability identified in HTTP::Body versions prior to 1.23_01 represents a significant resource exhaustion flaw within Perl-based web applications that utilize this module for parsing multipart form data. This library is commonly employed to handle file uploads and complex POST requests, where the body of an HTTP request is parsed into discrete parts based on MIME boundaries. The core technical deficiency lies in the lifecycle management of temporary files created during the parsing process. When the parser encounters the beginning of a file part within a multipart stream, it immediately creates a temporary file on disk to buffer incoming data. However, this temporary file is not added to an internal tracking list until the specific part has been fully parsed and completed. This design choice introduces a critical race condition or state inconsistency when parsing fails prematurely.
The operational impact of this flaw manifests as a denial-of-service vector through resource exhaustion. If an HTTP request containing a multipart body is terminated abruptly while inside a file part, such as by closing the connection before the boundary marker for that specific part is received, the parser completes its work but leaves behind the temporary file it created at the start of that segment. Because the incomplete part was never added to the internal upload list, there are no references held by the application object pointing to this file. Consequently, standard cleanup mechanisms or explicit deletion calls triggered upon successful parsing cannot locate or remove these orphaned files. The operating system retains ownership of the disk space until the process terminates and all open file descriptors are closed, but in long-running web server processes like those running under mod_perl, CGI wrappers with persistent states, or modern application servers using prefork workers, this cleanup may never occur automatically for that specific request context.
This behavior allows a remote attacker to systematically fill up the temporary directory allocated by the Perl interpreter or the underlying operating system. By repeatedly sending malformed multipart requests that are cut off mid-file part, an adversary can generate one orphaned temporary file per request. Over time, this accumulation consumes available disk space and potentially inodes on the filesystem hosting the web application. The resulting denial of service is not immediate but cumulative, leading to a gradual degradation of system performance until new files cannot be created, causing widespread failures for all services relying on that directory for transient data storage. This aligns with CWE-403, which describes insufficient control over resource consumption in multithreaded or concurrent environments, and can also be mapped to the Resource Exhaustion techniques found within the MITRE ATT&CK framework, specifically under Impact categories such as Denial of Service via disk space exhaustion.
Mitigation strategies for this vulnerability primarily involve upgrading to HTTP::Body version 1.23_01 or later, where the developers have addressed the lifecycle management issue by ensuring that temporary files are tracked from creation rather than completion. For environments unable to upgrade immediately, administrators should implement robust monitoring of disk space usage in the system's temporary directory and configure automated cleanup scripts to remove stale temporary files based on age rather than application state. Additionally, web server configurations can be tuned to enforce stricter timeouts for incoming connections and limit the maximum size of multipart requests, thereby reducing the window of opportunity for attackers to exploit this flaw effectively. Implementing rate limiting at the network perimeter further mitigates the risk by preventing a single source from rapidly generating the volume of malformed requests required to cause significant disk exhaustion.