Biosig libbiosig 3.9.0 MFER Parser biosig.c stack-based overflow

Summaryinfo

A vulnerability classified as critical was found in Biosig libbiosig 3.9.0. This issue affects some unknown processing of the file biosig.c of the component MFER Parser. Such manipulation leads to stack-based overflow. This vulnerability is traded as CVE-2025-54489. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in Biosig libbiosig 3.9.0 and classified as critical. Affected by this issue is an unknown function of the file biosig.c of the component MFER Parser. The manipulation with an unknown input leads to a stack-based overflow vulnerability. Using CWE to declare the problem leads to CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). Impacted is confidentiality, integrity, and availability. CVE summarizes:

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 8970 of biosig.c on the current master branch (35a819fa), when the Tag is 63: else if (tag==63) { uint8_t tag2=255, len2=255; count = 0; while ((count<len) && !(FlagInfiniteLength && len2==0 && tag2==0)){ curPos += ifread(&tag2,1,1,hdr); curPos += ifread(&len2,1,1,hdr); if (VERBOSE_LEVEL==9) fprintf(stdout,"MFER: tag=%3i chan=%2i len=%-4i tag2=%3i len2=%3i curPos=%i %li count=%4i\n",tag,chan,len,tag2,len2,curPos,iftell(hdr),(int)count); if (FlagInfiniteLength && len2==0 && tag2==0) break; count += (2+len2); curPos += ifread(&buf,1,len2,hdr); Here, the number of bytes read is not the Data Length decoded from the current frame in the file (`len`) but rather is a new length contained in a single octet read from the same input file (`len2`). Despite this, a stack-based buffer overflow condition can still occur, as the destination buffer is still `buf`, which has a size of only 128 bytes, while `len2` can be as large as 255.

The advisory is available at talosintelligence.com. This vulnerability is handled as CVE-2025-54489 since 07/23/2025. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 09/03/2025).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-25674). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• Biosig

Name

• libbiosig

Version

• 3.9.0

CPE 2.3info

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CPE 2.2info

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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