CVE-2026-112276 in Netpbm
Summary
by MITRE • 10/19/2026
Netpbm through 11.16.00 contains a heap out-of-bounds read vulnerability in rasttopnm that allows attackers to read heap memory by supplying Sun rasterfiles with short colormaps. Attackers can craft colormapped rasterfiles with pixel bytes exceeding the palette length to leak up to 255 adjacent heap bytes into the PNM output or crash the program.
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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 memory safety flaw located within the rasttopnm utility, which is responsible for converting Sun raster image files into various Portable Network Graphics formats. This specific defect manifests as a heap-based out-of-bounds read condition triggered by malformed input data rather than arbitrary code execution or direct system compromise. The root cause lies in insufficient validation of colormap dimensions during the parsing phase of the Sun rasterfile format. When processing these images, the software assumes that pixel indices will always fall within the bounds of the defined color palette. However, it fails to verify whether the actual pixel values contained in the image data exceed the length of the allocated colormap array before attempting to access them for conversion purposes.
From a technical perspective, this flaw allows an attacker who can supply crafted Sun rasterfiles with short colormaps to exploit the lack of boundary checks. By embedding pixel bytes that reference indices beyond the end of the palette buffer, the application proceeds to read memory locations adjacent to the heap-allocated colormap structure. This behavior results in the leakage of up to 255 additional bytes from the surrounding heap memory into the resulting PNM output stream or causes a segmentation fault if those addresses are unmapped. The ability to leak arbitrary heap contents is particularly dangerous as it can expose sensitive information such as stack pointers, cryptographic keys, or other process data that resides in close proximity within the virtual address space of the application.
The operational impact of this vulnerability extends beyond simple denial of service through crashes. While a crash would disrupt availability for users processing untrusted images, the primary concern is confidentiality due to the memory disclosure aspect. In scenarios where Netpbm is deployed as part of an automated pipeline or web-based image conversion service, feeding maliciously crafted files could allow remote attackers to exfiltrate internal application state information. This aligns with Common Weakness Enumeration category CWE-125, which describes out-of-bounds read vulnerabilities that enable the reading of memory beyond intended boundaries. Furthermore, this exploitation technique maps directly to MITRE ATT&CK tactic T1083, specifically the file and directory discovery subtechnique, as well as potential data exfiltration methods where leaked heap contents provide intelligence for further attacks against the host system or network infrastructure.
Mitigation strategies must prioritize immediate patching of Netpbm to version 12.00.00 or later, which includes corrections for this boundary validation logic. In environments where upgrading is not immediately feasible, administrators should implement strict input filtering at the perimeter level to reject Sun rasterfiles that exhibit anomalies in colormap size relative to pixel data length. Additionally, deploying runtime application self-protection mechanisms or memory-safe wrappers can help detect and block out-of-bounds access attempts before they result in information leakage. It is also advisable to restrict the execution privileges of processes utilizing Netpbm tools to minimize the potential impact if a successful exploitation occurs, adhering to the principle of least privilege commonly recommended for handling untrusted media inputs.