A stack-based buffer overflow vulnerability exists in the MFER parsing functionality of The Biosig Project libbiosig 3.9.0 and Master Branc…

A stack-based buffer overflow vulnerability exists in the MFER parsing functionality of The Biosig Project libbiosig 3.9.0 and Master Branch (35a819fa). A specially crafted MFER file can lead to arbitrary code execution. An attacker can provide a malicious file to trigger this vulnerability.This vulnerability manifests on line 9141 of biosig.c on the current master branch (35a819fa), when the Tag is 67:

else if (tag==67) //0x43: Sample skew
{
int skew=0; // [1]
curPos += ifread(&skew, 1, len,hdr);

In this case, the address of the newly-defined integer `skew` \[1\] is overflowed instead of `buf`. This means a stack overflow can occur using much smaller values of `len` in this code path.