Code execution via unchecked MFER patient-age length
Published Dec 11, 2025 · Updated Dec 11, 2025
Stack-based buffer overflow in The BioSig Project libbiosig 3.9.1 allows attackers to execute arbitrary code via a crafted MFER file. In the sopen_extended Tag 131 patient-age branch, the parser warns when the encoded length is not seven bytes but still passes that untrusted length to ifread, which copies into a fixed 128-byte stack buffer without a bounds check. Processing the file through a consuming application is sufficient to overwrite stack memory, causing a crash or enabling code execution in that application's context.
Summary
What happened
Stack-based buffer overflow in The BioSig Project libbiosig 3.9.1 allows attackers to execute arbitrary code via a crafted MFER file. In the sopen_extended Tag 131 patient-age branch, the parser warns when the encoded length is not seven bytes but still passes that untrusted length to ifread, which copies into a fixed 128-byte stack buffer without a bounds check. Processing the file through a consuming application is sufficient to overwrite stack memory, causing a crash or enabling code execution in that application's context.
The record
- CVE
- CVE-2025-66047
- Published
- Dec 11, 2025
- Updated
- Dec 11, 2025
- Vendor
- The BioSig Project
- Product
- libbiosig
- Classifications
- CWE-787, CWE-121
- 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 crafted-MFER proof of conceptproof of concept · unverified
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Technologies
Your stack
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Your stack
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