Stack-Based Buffer Overflow in Netpbm picttoppm

Executive Summary

CVE-2026-120434 is a stack-based buffer overflow in Netpbm's picttoppm utility, which converts Macintosh PICT files to PPM format. The vulnerability occurs in the scanPoly() function when processing polygon edges in a PICT file. Attackers can craft a file with over 5000 points, overflowing the coord stack array and causing crashes or potential code execution.

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Detection Guidance

To detect this vulnerability, inspect systems running vulnerable Netpbm versions by checking installed versions against patched releases (10.86.51, 11.02.30, 11.15.08). Monitor for crashes in picttoppm when processing PICT files. Use file integrity tools to detect unexpected changes in converter/ppm/picttoppm.c.

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Impact Analysis

This vulnerability could allow attackers to crash the picttoppm utility or execute arbitrary code by providing a malformed PICT file. If you process untrusted PICT files with vulnerable Netpbm versions, your system may be compromised, leading to data theft, system damage, or unauthorized access.

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Compliance Impact

This vulnerability could impact compliance with GDPR and HIPAA by enabling arbitrary code execution or denial-of-service attacks through crafted PICT files. If exploited, it may lead to unauthorized data access, modification, or system disruption, violating data integrity and availability requirements under these regulations.

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Mitigation Strategies

Immediately update Netpbm to patched versions (10.86.51, 11.02.30, or 11.15.08). Disable or restrict access to picttoppm utility if not required. Implement input validation for PICT files in applications using Netpbm. Monitor for exploitation attempts targeting PICT file parsing.

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