# CVE-2025-54481: biosig: A stack-based buffer overflow vulnerability exists in the MFER parsing functionality of The Biosig Project libbiosig...

CVE-2025-54481 is fixed in biosig on 1 platform by DEBIAN-CVE-2025-54481 (version 3.9.5-1), released August 25, 2025. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2025-54481
- Priority: Urgent
- CVSS: 9.8 (critical)
- EPSS: 0.0071
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 25, 2025

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | biosig Debian 14 | 3.9.5-1 | [DEBIAN-CVE-2025-54481](https://patchblox.com/security/data/fix/linux/debian-cve-2025-54481.md) | Aug 25, 2025 |

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