CVE-2026-22190 in Panda3D
Summary
by MITRE • 01/07/2026
The egg-mkfont utility in Panda3D versions up to and including 1.10.16 contains an uncontrolled format string vulnerability. The -gp (glyph pattern) command-line option is used directly as the format string for sprintf() with only a single argument supplied. If an attacker provides additional format specifiers, egg-mkfont may read unintended stack values and write the formatted output into generated .egg and .png files, resulting in disclosure of stack-resident memory and pointer values.
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Analysis
by VulDB Data Team • 05/27/2026
The vulnerability identified as CVE-2026-22190 resides within the Panda3D 3D graphics engine library, specifically affecting versions up to and including 1.10.16. This issue manifests in the egg-mkfont utility, which is responsible for generating font files in the .egg and .png formats. The flaw represents a classic format string vulnerability that arises from improper input validation and handling of user-supplied arguments. The vulnerability occurs when the utility processes the -gp (glyph pattern) command-line option, which is directly passed to the sprintf() function without proper sanitization or validation. This design flaw creates a dangerous condition where attacker-controlled input can manipulate the format string interpretation, leading to unintended memory access patterns and potential information disclosure.
The technical exploitation of this vulnerability stems from the improper use of the sprintf() function in C programming, where the format string parameter is directly derived from user input without adequate protection mechanisms. When an attacker supplies a malicious glyph pattern containing format specifiers such as %x, %s, or %p, the sprintf() function interprets these as instructions for reading from the stack and formatting data accordingly. The vulnerability is particularly concerning because it operates with only a single argument provided to sprintf(), which means that additional format specifiers in the input can cause the function to read from stack locations that contain sensitive data including memory addresses, pointer values, and potentially other stack-resident information. This uncontrolled format string behavior can result in partial or complete disclosure of stack memory contents, which may contain sensitive information such as return addresses, local variables, or other program state data that could be leveraged for further exploitation.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates potential pathways for more sophisticated attacks within the context of the affected software ecosystem. When the vulnerable egg-mkfont utility generates .egg and .png font files, the attacker-controlled format specifiers can be embedded within these files, potentially leading to information leakage that could aid in bypassing security mechanisms such as address space layout randomization or stack canaries. The vulnerability affects the integrity of generated font assets and could potentially be exploited by attackers to gain insights into the memory layout of processes using Panda3D, particularly in scenarios where these font files are processed by other components of the application or system. The exposure of stack-resident memory values could provide attackers with critical information needed for advanced exploitation techniques including return-oriented programming or other binary exploitation methods. According to CWE classification, this vulnerability maps to CWE-134, which specifically addresses the use of format strings with user-supplied data, and aligns with ATT&CK technique T1059.008 for the use of command and scripting interpreter where the format string vulnerability could be leveraged to execute unintended code or commands through manipulated input processing.
Mitigation strategies for this vulnerability should focus on immediate code-level fixes and broader security practices within the Panda3D ecosystem. The primary remediation involves modifying the egg-mkfont utility to properly sanitize and validate all user-supplied input before processing, particularly the -gp command-line option. This can be achieved by implementing proper format string handling techniques such as using snprintf() with appropriate buffer sizes or by ensuring that user input is treated as literal strings rather than format specifiers. The recommended approach includes either escaping or filtering format specifiers from user input, or constructing format strings that explicitly use the user input as a literal argument rather than as a format specification. Organizations should also implement comprehensive input validation at the application level, ensuring that all command-line options are properly sanitized before being passed to low-level string manipulation functions. Additionally, regular security audits and static code analysis of the Panda3D codebase should be conducted to identify similar patterns that could lead to format string vulnerabilities or other input validation issues. System administrators should consider implementing access controls and limiting execution privileges for the affected utility, while developers should follow secure coding guidelines that specifically address the prevention of format string vulnerabilities in C and C++ applications. The vulnerability underscores the importance of defensive programming practices and proper input handling in security-critical applications, particularly those that process user-supplied data in low-level system functions.