Summary
A stack-based buffer overflow vulnerability exists in the MFER parsing functionality of The...
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.
Impact
CVE-2025-54489 has a CVSS score of 9.8 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-54489? CVE-2025-54489 is a critical-severity security vulnerability. No fixed version is listed yet.
- How severe is CVE-2025-54489? CVE-2025-54489 has a CVSS score of 9.8 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2025-54489? No fixed version is listed for CVE-2025-54489 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-54489 exploitable, and should I be worried? Whether CVE-2025-54489 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-54489 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.