CVE-2026-22189: Panda3D <= 1.10.16 egg-mkfont Stack Buffer Overflow

The egg-mkfont utility in Panda3D versions up to and including 1.10.16 contains a stack-based buffer overflow vulnerability due to use of an unbounded sprintf() call with attacker-controlled input. When constructing glyph filenames, egg-mkfont formats a user-supplied glyph pattern (-gp) into a fixed-size stack buffer without length validation. Supplying an excessively long glyph pattern string can overflow the stack buffer, resulting in memory corruption and a deterministic crash. Depending on build configuration and execution environment, the overflow may also be exploitable for arbitrary code execution.