An issue was discovered in mspack/chmd.c in libmspack before 0.7alpha. There is an off-by-one error in the CHM PMGI/PMGL chunk number validity checks, which could lead to denial of service (uninitialized data dereference and application crash).
A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.