An issue was discovered in mspack/chmd.c in libmspack before 0.7alpha. There is an off-by-one error in the TOLOWER() macro for CHM decompression.
Exploitability
AV:NAC:LPR:NUI:RScope
S:UImpact
C:HI:HA:H8.8/CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H