CVE-2025-54490VulnerabilityPublished 25 Aug 2025Updated 3 Nov 2025

CVE-2025-54490: 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 repositories and security advisories closely for official patches addressing CVE-2025-54490 and apply them promptly once released. 2. Until patches are available, implement strict input validation on MFER files before processing, including enforcing maximum length constraints on fields to prevent buffer overflows. 3. Employ runtime protections such as stack canaries, Address Space Layout Randomization (ASLR), and Data Execution Prevention (DEP) on systems running libbiosig to mitigate exploitation impact. 4. Restrict access to systems processing MFER files by limiting network exposure and applying strict access controls to reduce the attack surface. 5. Conduct code audits and static analysis on custom integrations of libbiosig to identify and remediate unsafe buffer handling. 6. Deploy intrusion detection systems capable of detecting anomalous MFER file inputs or exploitation attempts. 7. Educate developers and system administrators about the vulnerability to ensure awareness and prompt response. 8. Consider sandboxing or isolating biosignal processing components to contain potential exploitation effects. 9. Maintain comprehensive backups and incident response plans tailored to potential exploitation scenarios involving biosignal processing systems.

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 9090 of biosig.c on the current master branch (35a819fa), when the Tag is 64: else if (tag==64) //0x40 { // preamble char tmp[256]; // [1] curPos += ifread(tmp,1,len,hdr); In this case, the overflowed buffer is the newly-declared `tmp` \[1\] instead of `buf`. While `tmp` is larger than `buf`, having a size of 256 bytes, a stack overflow can still occur in cases where `len` is encoded using multiple octets and is greater than 256.

Impact

The impact of CVE-2025-54490 on European organizations is substantial, particularly for those in healthcare, biomedical research, and related industries that utilize biosignal processing software incorporating libbiosig. Successful exploitation can lead to arbitrary code execution, allowing attackers to compromise system confidentiality, integrity, and availability. This could result in unauthorized access to sensitive patient data, manipulation or disruption of medical device functionality, and potential safety risks to patients. Additionally, compromised research environments could lead to data tampering or intellectual property theft. The vulnerability's network attack vector and lack of required privileges mean attackers can exploit it remotely by delivering malicious MFER files, increasing the threat surface. Given the criticality of healthcare infrastructure in Europe and stringent data protection regulations like GDPR, the consequences of exploitation include regulatory penalties, reputational damage, and operational disruptions. The absence of known exploits currently provides a window for proactive mitigation, but the ease of exploitation and critical severity necessitate urgent action to prevent potential attacks.

Summary

CVE-2025-54490 is a stack-based buffer overflow vulnerability identified in The Biosig Project's libbiosig library, specifically in the MFER file parsing code. The vulnerability arises in the function handling tag 64 (0x40) where a local buffer 'tmp' of 256 bytes is allocated on the stack. The code reads 'len' bytes from the input file into this buffer without adequately verifying that 'len' does not exceed 256. Since 'len' can be encoded using multiple octets, an attacker can craft an MFER file with a length field larger than 256, causing a buffer overflow on the stack. This overflow can overwrite adjacent stack data, including return addresses, enabling arbitrary code execution. The vulnerability affects libbiosig version 3.9.0 and the current master branch (commit 35a819fa). The CVSS 3.1 base score is 9.8, indicating critical severity with network attack vector, low attack complexity, no privileges or user interaction required, and full impact on confidentiality, integrity, and availability. No public exploits are known yet, but the vulnerability is straightforward to exploit by delivering a malicious MFER file to a system processing biosignal data with libbiosig. This poses a significant risk to applications relying on libbiosig for biosignal analysis, including medical devices, research tools, and healthcare software. The vulnerability's root cause is improper input validation and unsafe buffer handling in biosig.c at line 9090. Without patches currently available, organizations must implement compensating controls to mitigate risk.

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, 20:33 UTC

WeaknessesCWE-121

Technical details

References

Community reviews

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