In radare2 through 3.1.3 the armass_assemble function in libr/asm/arch/arm/armass.c allows attackers to cause a denial-of-service (application crash by out-of-bounds read) by crafting an arm assembly input because a loop uses an incorrect index in armass.c and certain length validation is missing in armass64.c a related issue to CVE-2018-20457.