CVE-2026-20777Public exploitNetwork attack vector

Code execution via unbounded WFT field copy

Published Mar 3, 2026 · Updated Mar 3, 2026

Heap-based buffer overflow in libbiosig 3.9.2 and Master Branch (db9a9a63) allows remote attackers to execute code via a WFT file. In sopen_extended, strcpy copies the unbounded Nicolet_Digitizer_Type field at offset 8 into the 129-byte hdr->ID.Manufacturer._field buffer. Processing a crafted WFT file triggers the overwrite; _FORTIFY_SOURCE terminates affected builds, while unfortified builds permit attacker-controlled heap corruption and code execution.

CVSS severity8.1
High
EPSS probability0.51%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in libbiosig 3.9.2 and Master Branch (db9a9a63) allows remote attackers to execute code via a WFT file. In sopen_extended, strcpy copies the unbounded Nicolet_Digitizer_Type field at offset 8 into the 129-byte hdr->ID.Manufacturer._field buffer. Processing a crafted WFT file triggers the overwrite; _FORTIFY_SOURCE terminates affected builds, while unfortified builds permit attacker-controlled heap corruption and code execution.

The record

CVE
CVE-2026-20777
Published
Mar 3, 2026
Updated
Mar 3, 2026
Vendor
The BioSig Project
Product
libbiosig
Classifications
CWE-122, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 3, 2026Record 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.

  1. Affected versionversion=3.9.2
  2. Affected versionversion=Master Branch (db9a9a63)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The BioSig Project · libbiosigversion=3.9.2; version=Master Branch (db9a9a63)

Published CVSS scores

8.1Cisco TalosCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1203Exploitation for Client Execution

Public exploit references

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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