CVE-2025-54481

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 8744 of biosig.c on the current master branch (35a819fa), when the Tag is 3:

				else if (tag==3) {
					// character code
					char v[17];		// [1]
					if (len>16) fprintf(stderr,"Warning MFER tag2 incorrect length %i>16\n",len);
					curPos += ifread(&v,1,len,hdr);
					v[len]  = 0;

In this case, the overflowed buffer is the newly-declared `v` \[1\] instead of `buf`. Since `v` is only 17 bytes large, much smaller values of `len` (even those encoded using a single octet) can trigger an overflow in this code path.