PackLinuxElf64::unpack in p_lx_elf.cpp in UPX 3.95 allows remote attackers to cause a denial of service (double free), limit the ability of a malware scanner to operate on the entire original data, or possibly have unspecified other impact via a crafted file.

p_mach.cpp in UPX 3.94 allows remote attackers to cause a denial of service (invalid memory access and application crash) or possibly have unspecified other impact via a crafted Mach-O file, related to canPack and unpack functions. NOTE: the vendor has stated "there is no security implication whatsoever.

p_lx_elf.cpp in UPX 3.94 mishandles ELF headers, which allows remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via a crafted binary file, as demonstrated by an Invalid Pointer Read in PackLinuxElf64::unpack().