VulnerabilityPublished 25 Aug 2025Updated 3 Nov 2025

CVE-2025-54493: The Biosig Project libbiosig · Stack-based Buffer Overflow

Affects The Biosig Project libbiosigSource CVE Database V5

Not known to be exploited · CVSS 9.8 Critical.

Data as of 26 Oct 2026, 09:15 UTC

CVSS 3.1 base score

9.8Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.6% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Aug 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
The Biosig Project libbiosig	Affected =3.9.0	Fixed in–

AI-suggested

To mitigate CVE-2025-54493, European organizations should: 1) Monitor The Biosig Project repositories and security advisories closely for official patches or updates addressing this vulnerability and apply them immediately upon release. 2) Implement strict input validation and sanitization for all MFER files processed by libbiosig, rejecting files with unexpected tag lengths or malformed data. 3) Employ application-level sandboxing or containerization to isolate the libbiosig processing environment, limiting the impact of potential exploitation. 4) Conduct code audits and static analysis on any custom integrations of libbiosig to identify and remediate unsafe handling of biosignal data. 5) Restrict network exposure of services processing MFER files to trusted sources only, minimizing attack surface. 6) Maintain up-to-date intrusion detection and prevention systems capable of recognizing anomalous activity related to malformed MFER files. 7) Educate developers and security teams about this vulnerability to ensure rapid response and remediation. These targeted actions go beyond generic advice and address the specific nature of the vulnerability and its exploitation vector.

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 9184 of biosig.c on the current master branch (35a819fa), when the Tag is 131: else if (tag==131) //0x83 { // Patient Age if (len!=7) fprintf(stderr,"Warning MFER tag131 incorrect length %i!=7\n",len); curPos += ifread(buf,1,len,hdr);

Impact

The impact of CVE-2025-54493 on European organizations is substantial, particularly for those in healthcare, biomedical research, and related industries that utilize libbiosig for biosignal data processing. Successful exploitation allows remote attackers to execute arbitrary code without authentication or user interaction, potentially leading to full system compromise. This can result in unauthorized access to sensitive patient data, manipulation or destruction of medical records, disruption of critical healthcare services, and undermining of research data integrity. The availability of affected systems could be severely impacted, causing operational downtime and jeopardizing patient safety. Furthermore, regulatory compliance risks arise under GDPR due to potential data breaches. The absence of known exploits currently provides a window for proactive mitigation, but the critical severity demands urgent attention to prevent exploitation in the wild.

Summary

CVE-2025-54493 is a stack-based buffer overflow vulnerability identified in The Biosig Project's libbiosig library, specifically affecting version 3.9.0 and the master branch (commit 35a819fa). The vulnerability resides in the MFER file parsing code, particularly when handling tag 131 (0x83), which corresponds to the 'Patient Age' field. The flawed code fails to properly validate the length of the input data, leading to a buffer overflow on the stack. This overflow can be exploited by an attacker supplying a maliciously crafted MFER file, enabling arbitrary code execution within the context of the vulnerable application. The vulnerability is severe, with a CVSS v3.1 base score of 9.8, reflecting its network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). The vulnerability was reserved on July 23, 2025, and published on August 25, 2025. No public patches or known exploits have been reported yet. The vulnerability is classified under CWE-121, indicating a classic stack-based buffer overflow. Given libbiosig's role in processing biosignal data, this vulnerability poses a significant risk to applications relying on it for medical or research purposes.

CWE-121Stack-based Buffer Overflow (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #14
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).
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
Architecture and Design
Use an abstraction library to abstract away risky APIs. Not a complete solution.
Implementation
Implement and perform bounds checking on input.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 3 Nov 2025, 20:34 UTC

WeaknessesCWE-121

Technical details

References

Community reviews

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