CVE-2026-102504 in Imager
Summary
by MITRE • 10/01/2026
Imager versions before 1.037 for Perl exit the process reading a raw image with an out-of-range raw_datachannels value in i_readraw_wiol.
Nothing range-checks raw_datachannels. The line buffer is sized as the image width times the channel count with no overflow check, so a negative or very large count requests an excessive allocation. When it fails, Imager's allocator calls exit(3).
Passing an untrusted raw_datachannels value to Imager->read() triggers an uncatchable exit.
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Analysis
by VulDB Data Team • 10/01/2026
The vulnerability identified in the Perl Imager module prior to version 1.037 represents a critical denial of service condition arising from insufficient input validation during image processing operations. Specifically, the flaw resides within the i_readraw_wiol function which is responsible for handling raw image data streams. The core technical deficiency involves the lack of range checking on the raw_datachannels parameter provided by the user or application consuming the library. In a secure implementation, any integer value derived from external input that dictates memory allocation size must be rigorously validated against expected bounds to prevent resource exhaustion or corruption. Here, the system fails to verify whether the channel count is within a logical range for image data processing, allowing negative integers or excessively large positive values to pass through unchecked into subsequent computational steps.
The operational mechanism of this vulnerability exploits how memory buffers are allocated based on user-supplied parameters. The line buffer size calculation multiplies the image width by the raw_datachannels value without performing any overflow detection or boundary validation. When a malicious actor supplies an untrusted and extreme value for raw_datachannels, the resulting allocation request becomes either excessively large due to integer overflow wrapping around to a small positive number followed by further miscalculation, or directly requests an amount of memory that exceeds system limits if interpreted as a very large unsigned integer. In scenarios where the underlying allocator fails to satisfy this excessive request, rather than returning an error code that allows for graceful handling within the application logic, Imager invokes exit(3). This call terminates the entire process immediately and unconditionally.
This behavior results in a severe denial of service impact because the termination is uncachable by standard exception handlers or signal traps available to Perl scripts. Applications relying on this library cannot recover from such an event without restarting the parent process, which may lead to significant downtime if the vulnerability can be triggered remotely via web services or networked applications that accept image uploads. The lack of error handling means that a single crafted input packet containing a malformed raw_datachannels value is sufficient to crash the hosting application, effectively rendering it unavailable for subsequent requests until manual intervention occurs.
From a classification perspective, this issue aligns with CWE-20 Improper Input Validation as the root cause lies in the failure to validate user-supplied data before processing. Furthermore, because the vulnerability leads to process termination and service disruption without requiring authentication or privilege escalation, it maps directly to ATT&CK technique T1499 Endpoint Denial of Service under the Impact tactic. Attackers can leverage this flaw to disrupt availability by sending specifically crafted image files through any interface that utilizes Imager for parsing raw image formats.
Mitigation strategies must prioritize immediate upgrading to version 1.037 or later where these checks have been implemented. For environments unable to upgrade immediately, defensive programming practices should be adopted at the application layer. This includes implementing strict type checking and range validation on all inputs passed to Imager functions before invocation. Additionally, deploying runtime protection mechanisms such as process supervision tools that can automatically restart crashed services may help mitigate availability impacts, although this does not address the underlying code flaw. Security teams should also audit other areas of their image processing pipeline for similar patterns where memory allocation sizes are derived directly from untrusted external inputs without adequate boundary checks.