CVE-2026-112275 in Netpbm
Summary
by MITRE • 10/19/2026
Netpbm through 11.16.00 contains a heap out-of-bounds write vulnerability in the rasttopnm Sun rasterfile run-length decoder pr_load_image in converter/other/rast.c. Attackers can supply a byte-encoded rasterfile with tiny dimensions and a long run-length body to write controlled bytes past md_image, causing memory corruption and crashes.
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Analysis
by VulDB Data Team • 10/19/2026
The vulnerability identified in Netpbm versions through 11.16.00 represents a critical heap-based buffer overflow located within the rasttopnm utility, specifically inside the pr_load_image function responsible for decoding Sun rasterfile run-length encoded data. This component is part of the broader image processing suite and handles various legacy graphics formats, including the proprietary Sun RasterFile format which utilizes run-length encoding to compress image data efficiently. The flaw arises from an insufficient validation mechanism when parsing the header information versus the subsequent pixel data stream. Specifically, the decoder calculates buffer sizes based on the width and height dimensions provided in the file header but fails to adequately verify that the length of the encoded run-length body does not exceed the allocated memory space for those specific dimensions. This discrepancy allows an attacker who supplies a maliciously crafted rasterfile with deceptively small dimension values paired with an excessively long run-length data section to force the application to write bytes beyond the boundaries of the md_image buffer.
From a technical perspective, this is classified as CWE-120 Buffer Copy without Checking Size of Input Expected to be Truncated or more specifically CWE-787 Out-of-bounds Write in C/C++ contexts. The operational mechanism involves the attacker constructing a file where the header declares minimal spatial constraints while the payload contains redundant data sequences that, when decoded and written into memory, overwrite adjacent heap structures. This out-of-bands write corrupts critical metadata or control pointers stored on the heap immediately following the image buffer. Such corruption typically manifests as application crashes due to segmentation faults when the program attempts to access invalid memory addresses or free corrupted memory blocks during cleanup routines. However, in more sophisticated exploitation scenarios involving specific allocator behaviors and adjacent object layouts, this memory corruption could potentially be leveraged for arbitrary code execution by overwriting function pointers or return addresses on the heap, although such exploits require precise knowledge of the runtime environment and allocation patterns.
The impact of this vulnerability extends beyond simple denial-of-service conditions caused by application crashes. For systems that process untrusted image inputs from external sources, such as web servers accepting uploads for preview generation or automated pipelines processing scanned documents, this flaw poses a significant risk to system integrity. An attacker could exploit the memory corruption to escalate privileges if the vulnerable service runs with elevated permissions, thereby gaining unauthorized access to sensitive data or using the compromised host as a pivot point within an internal network. The presence of this vulnerability in widely used image conversion tools highlights the persistent risks associated with legacy format parsers that may not have undergone rigorous modern security auditing compared to more contemporary formats like PNG or JPEG which often benefit from stricter standardization and community scrutiny over time.
Mitigation strategies for this issue primarily involve upgrading Netpbm to a version later than 11.16.00 where the vulnerability has been patched with proper bounds checking logic in the pr_load_image function. In environments where immediate patching is not feasible, administrators should implement strict input validation at the network perimeter or application layer to reject rasterfiles that exhibit disproportionate ratios between declared dimensions and data payload sizes. Additionally, deploying runtime protection mechanisms such as heap hardening features available in modern compilers like AddressSanitizer during development or utilizing exploit prevention technologies like Data Execution Prevention and stack canaries can help mitigate the impact of successful exploitation attempts by detecting memory corruption events before they lead to code execution. Security teams should also audit their usage of legacy image processing utilities against known vulnerable formats and restrict access to these tools where possible, adhering to the principle of least privilege to minimize the attack surface associated with handling untrusted graphical data inputs as defined in ATT&CK techniques related to initial exploitation via client-side components or file format parsing.