Pillow is a Python imaging library. From 10.0.0 until 13.0.0, Pillow can free an invalid glyph pointer during FreeType rendering with an active stroker. If FT_Load_Glyph fails, cleanup may call FT_Done_Glyph on an uninitialized or stale glyph variable. An attacker can supply a malformed font as untrusted bytes to an application that draws text with a nonzero stroke width, forcing the glyph-load failure path. This can corrupt memory or crash the process. This issue is fixed in version 13.0.0.