0xFEEEFEEE

Win32 freed heap

category: sentinel
normalized: feeefeee
confirmed: 2026-05-19
lookups: 1
source: https://en.wikipedia.org/wiki/Magic_number_(programming)

Pattern written by Microsoft's debug HeapFree over freed heap memory. Seeing it in a crash dump means use-after-free.

Similar magic numbers

value	name	category
FE EF	Symantex Ghost image file	file-signature
FE ED FE ED	JavaKeyStore	file-signature
FE ED FA CF	OS X ABI Mach-O binary (64-bit)	file-signature
0xFEEDFACE	Mach-O binary (32-bit)	file-signature
FE FF	UTF-16-UCS-2 file	file-signature