CVE-2025-54481VulnerabilityPublished 25 Aug 2025Updated 3 Nov 2025

CVE-2025-54481: 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 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

9.8Critical

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

EPSS: 0.7% chance of exploitation in 30 days – higher than 53% 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 2026-10-25.

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

1. Monitor The Biosig Project's official channels for patches addressing CVE-2025-54481 and apply updates promptly once available. 2. Until patches are released, implement strict input validation to reject MFER files with suspiciously large or malformed tags, especially those with tag '3' and length fields exceeding 16 bytes. 3. Employ sandboxing or isolation techniques for applications processing MFER files to contain potential exploitation attempts. 4. Conduct code audits and static analysis on custom integrations of libbiosig to identify and remediate unsafe parsing practices. 5. Restrict network exposure of services that accept MFER files to trusted sources only, and implement file integrity checks and scanning for malicious payloads. 6. Enhance monitoring and logging around biosignal processing systems to detect anomalous behavior indicative of exploitation attempts. 7. Educate developers and system administrators about this vulnerability to ensure rapid response and mitigation in affected environments.

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.

Impact

For European organizations, the impact of CVE-2025-54481 can be severe, particularly in sectors relying on biosignal processing such as healthcare, biometric authentication, and research institutions. Exploitation could lead to arbitrary code execution, enabling attackers to compromise system confidentiality, integrity, and availability. This could result in unauthorized access to sensitive patient data, manipulation of biometric authentication systems, or disruption of critical medical devices and research operations. Given the critical CVSS score and the lack of required authentication or user interaction, attackers could remotely exploit vulnerable systems by delivering malicious MFER files, potentially through network services or file-sharing mechanisms. The disruption or compromise of healthcare and biometric systems could have cascading effects on patient safety, privacy compliance (e.g., GDPR), and operational continuity. Additionally, organizations may face regulatory penalties and reputational damage if breaches occur due to this vulnerability.

Summary

CVE-2025-54481 is a stack-based buffer overflow vulnerability identified in the MFER parsing functionality of The Biosig Project's libbiosig library, specifically in versions 3.9.0 and the master branch (commit 35a819fa). The vulnerability arises from improper bounds checking when reading character data tagged as '3' into a fixed-size buffer 'v' of 17 bytes. The code reads 'len' bytes from the input file into 'v' without adequately ensuring that 'len' does not exceed the buffer size, leading to a buffer overflow on the stack. This overflow can corrupt adjacent memory, potentially allowing an attacker to execute arbitrary code with the privileges of the application using libbiosig. The vulnerability is triggered by supplying a maliciously crafted MFER file, a format used for biosignal data. The flaw is located at line 8744 in biosig.c, where the code attempts to read and null-terminate the buffer without sufficient length validation. The CVSS v3.1 base score is 9.8, reflecting the vulnerability's critical nature due to network attack vector, no required privileges or user interaction, and full impact on confidentiality, integrity, and availability. No public exploits are known yet, but the vulnerability's characteristics make it highly exploitable once weaponized. The Biosig Project is a widely used open-source library in biosignal processing applications, including medical devices and biometric systems, which increases the potential attack surface.

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

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 3 Nov 2025, 19:43 UTC

WeaknessesCWE-121

Technical details

References

Community reviews

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