CVE-2025-54483 in libbiosig
Summary
by MITRE • 08/25/2025
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 8759 of biosig.c on the current master branch (35a819fa), when the Tag is 5:
else if (tag==5) //0x05: number of channels {
uint16_t oldNS=hdr->NS; if (len>4) fprintf(stderr,"Warning MFER tag5 incorrect length %i>4\n",len); curPos += ifread(buf,1,len,hdr);
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Analysis
by VulDB Data Team • 09/02/2025
The vulnerability CVE-2025-54483 represents a critical stack-based buffer overflow in the libbiosig library version 3.9.0 and master branch revision 35a819fa, specifically within the MFER file parsing functionality. This issue arises from inadequate input validation when processing the Tag 5 field in MFER files, which is designated for specifying the number of channels. The flaw occurs in the biosig.c source file at line 8759, where the library fails to properly validate the length parameter before proceeding with data processing, creating a potential pathway for remote code execution through crafted malicious files.
The technical implementation of this vulnerability stems from the insufficient bounds checking mechanism during MFER file parsing operations. When the parser encounters Tag 5 with a length value exceeding four bytes, the code path executes a warning message but continues processing without proper validation of the buffer boundaries. The variable curPos is incremented using ifread function with the potentially untrusted len parameter, which can result in writing beyond the allocated stack buffer space. This particular code pattern aligns with CWE-121 Stack-based Buffer Overflow, where insufficient validation allows attackers to overwrite adjacent stack memory locations. The vulnerability's exploitability is significantly enhanced because the MFER format is commonly used for medical data exchange, making it a prime target for attackers seeking to compromise systems processing such sensitive information.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it enables arbitrary code execution capabilities that could be leveraged by threat actors. Attackers can craft malicious MFER files with oversized Tag 5 fields to overwrite return addresses or other critical stack variables, potentially leading to complete system compromise. This vulnerability affects systems that utilize libbiosig for processing medical data files, particularly those in healthcare environments where data integrity and system security are paramount. The attack surface is broadened by the library's widespread adoption in medical device firmware and research applications, where the processing of potentially malicious files may occur in unattended or automated environments.
Mitigation strategies for CVE-2025-54483 should prioritize immediate patching of affected libbiosig installations to the latest stable release containing the fix for this buffer overflow vulnerability. Organizations should implement strict input validation measures for all MFER file processing operations, including length parameter verification and buffer boundary checks before any data is read into memory. Network segmentation and access controls should be enforced to limit exposure of systems that process MFER files, particularly in healthcare environments where such attacks could have severe consequences. Additionally, implementing runtime protection mechanisms such as stack canaries, address space layout randomization, and data execution prevention can provide additional defense-in-depth layers. This vulnerability's characteristics align with ATT&CK technique T1203 Exploitation for Client Execution, where attackers leverage software vulnerabilities to execute malicious code on target systems through crafted input files.