Code execution via unchecked MFER Tag 133 length
Published Dec 11, 2025 · Updated Dec 11, 2025
Stack-based buffer overflow in libbiosig 3.9.1 allows attackers to execute arbitrary code through a crafted MFER file with Tag 133. In sopen_extended, the Tag 133 branch passes the attacker-controlled MFER length to ifread for a fixed 128-byte stack buffer without checking that the value fits. Exploitation requires a consuming application to parse the file; the overwrite can crash that process or execute code in its context.
Summary
What happened
Stack-based buffer overflow in libbiosig 3.9.1 allows attackers to execute arbitrary code through a crafted MFER file with Tag 133. In sopen_extended, the Tag 133 branch passes the attacker-controlled MFER length to ifread for a fixed 128-byte stack buffer without checking that the value fits. Exploitation requires a consuming application to parse the file; the overwrite can crash that process or execute code in its context.
The record
- CVE
- CVE-2025-66048
- Published
- Dec 11, 2025
- Updated
- Dec 11, 2025
- Vendor
- The BioSig Project
- Product
- libbiosig
- Classifications
- CWE-121, CWE-787
- 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.
Public exploit references
- Cisco Talos MFER Tag 133 proof of conceptproof of concept · unverified
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Technologies
Your stack
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Your stack
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