CVE-2020-14199Network attack vector

Excessive transaction fees via recombined Segwit signatures

Published Jun 16, 2020 · Updated Aug 4, 2024

Improper signature verification in BIP-143 hardware wallets allows remote attackers to induce excessive Bitcoin transaction fees. BIP-143 binds each Segwit input amount only to its own signature, allowing signatures from two user-approved transactions to be recombined into a third transaction with larger real inputs. Malicious wallet software must control the proposed transactions and persuade the user to confirm two apparently identical requests, after which the recombined transaction can consume the difference as a fee.

CVSS severity6.5
Medium
EPSS probability0.85%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper signature verification in BIP-143 hardware wallets allows remote attackers to induce excessive Bitcoin transaction fees. BIP-143 binds each Segwit input amount only to its own signature, allowing signatures from two user-approved transactions to be recombined into a third transaction with larger real inputs. Malicious wallet software must control the proposed transactions and persuade the user to confirm two apparently identical requests, after which the recombined transaction can consume the difference as a fee.

The record

CVE
CVE-2020-14199
Published
Jun 16, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-347, T1204
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 16, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1204User Execution

Public exploit references

No public exploit references are available in this record.

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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