Code execution via unchecked Tag 64 length
Published Dec 11, 2025 · Updated Dec 11, 2025
Stack-based buffer overflow in libbiosig 3.9.1 allows remote attackers to execute arbitrary code via a crafted Tag 64 MFER file. The Tag 64 branch of sopen_extended passes the attacker-controlled MFER length to ifread, which copies that many bytes into a 256-byte stack buffer without checking its capacity. Exploitation requires an application using the library to parse the supplied file and grants code execution in that application's process.
Summary
What happened
Stack-based buffer overflow in libbiosig 3.9.1 allows remote attackers to execute arbitrary code via a crafted Tag 64 MFER file. The Tag 64 branch of sopen_extended passes the attacker-controlled MFER length to ifread, which copies that many bytes into a 256-byte stack buffer without checking its capacity. Exploitation requires an application using the library to parse the supplied file and grants code execution in that application's process.
The record
- CVE
- CVE-2025-66044
- Published
- Dec 11, 2025
- Updated
- Dec 11, 2025
- Vendor
- The BioSig Project
- Product
- libbiosig
- Classifications
- CWE-787, CWE-121, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 11, 2025CVE publishedPublication date reported by the CVE source.
- Dec 11, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=3.9.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Cisco Talos Tag 64 MFER proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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