CVE-2025-54487VulnerabilityPublished 25 Aug 2025Updated 3 Nov 2025

CVE-2025-54487: 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: 0.6% 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 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 for official patches addressing CVE-2025-54487 and apply them immediately upon release. 2. Until patches are available, implement strict input validation to reject MFER files with suspicious or out-of-range length values, especially those with 'len' less than 2 or greater than 130. 3. Employ sandboxing or isolated environments for processing MFER files to contain potential exploitation attempts. 4. Conduct code audits and static analysis on any custom integrations of libbiosig to identify and remediate similar unsafe parsing patterns. 5. Restrict file sources and enforce strict access controls to minimize exposure to malicious MFER files, particularly in networked or shared environments. 6. Increase monitoring and logging around systems processing biosignal data to detect anomalous behavior indicative of exploitation attempts. 7. Educate developers and security teams about the risks of unsafe buffer handling and the specifics of this vulnerability to improve future resilience.

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 8842 of biosig.c on the current master branch (35a819fa), when the Tag is 12: else if (tag==12) //0x0C { // sampling resolution if (len>6) fprintf(stderr,"Warning MFER tag12 incorrect length %i>6\n",len); val32 = 0; int8_t v8; curPos += ifread(&UnitCode,1,1,hdr); curPos += ifread(&v8,1,1,hdr); curPos += ifread(buf,1,len-2,hdr); In addition to values of `len` greater than 130 triggering a buffer overflow, a value of `len` smaller than 2 will also trigger a buffer overflow due to an integer underflow when computing `len-2` in this code path.

Impact

For European organizations, the impact of CVE-2025-54487 is significant, especially in sectors relying on biosignal processing such as healthcare providers, medical device manufacturers, and research institutions. Exploitation could lead to arbitrary code execution, allowing attackers to compromise sensitive patient data, disrupt medical device functionality, or manipulate research data integrity. This could result in severe privacy violations, operational downtime, and potential harm to patients if medical devices are affected. The vulnerability’s remote and unauthenticated nature increases the risk of widespread exploitation. Given Europe's stringent data protection regulations like GDPR, breaches resulting from this vulnerability could also lead to substantial legal and financial penalties. Additionally, disruption in healthcare services could have broader societal impacts. Organizations using libbiosig in their software stacks must prioritize mitigation to prevent exploitation.

Summary

The vulnerability CVE-2025-54487 is a stack-based buffer overflow in the Biosig Project's libbiosig library, specifically in the MFER file parsing code. The issue occurs in biosig.c at line 8842 when processing tag 12 (0x0C), which relates to sampling resolution data. The code reads a length value 'len' from the MFER file and then attempts to read 'len-2' bytes into a fixed-size buffer without proper bounds checking. If 'len' exceeds 130, the buffer overflow occurs due to writing beyond the buffer's allocated size. Conversely, if 'len' is less than 2, an integer underflow causes 'len-2' to become a large unsigned integer, also leading to a buffer overflow. This improper validation allows an attacker to craft malicious MFER files that, when parsed by libbiosig, can overwrite the stack and potentially execute arbitrary code. The vulnerability requires no authentication or user interaction and can be triggered remotely by supplying a malicious file. The CVSS 3.1 score of 9.8 reflects the high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges required. The Biosig Project is used in biosignal processing, often in medical and research contexts, making this vulnerability particularly concerning for sensitive environments. No patches are currently linked, and no exploits are known in the wild, but the critical nature demands proactive mitigation.

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, 19:45 UTC

WeaknessesCWE-121

Technical details

References

Community reviews

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