canUnpack in p_vmlinx.cpp in UPX 3.95 allows remote attackers to cause a denial of service (SEGV or buffer overflow, and application crash) or possibly have unspecified other impact via a crafted UPX packed file.
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.