CVE-2025-66017Network attack vector

Signature forgery via raw-hash presignature misuse

Published Nov 25, 2025 · Updated Nov 25, 2025

Cryptographic weakness in cggmp21 0.6.3 and earlier and cggmp24 0.7.0-alpha.1 allows remote attackers to forge ECDSA signatures. Presignature::issue_partial_signature accepts an attacker-chosen digest without requiring the original message, while set_derivation_path applies a chosen HD path to a presignature. Exploitation requires raw-hash signing or post-presignature HD derivation; the former enables forgery and the latter lowers security to 85 bits.

CVSS severity8.2
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cryptographic weakness in cggmp21 0.6.3 and earlier and cggmp24 0.7.0-alpha.1 allows remote attackers to forge ECDSA signatures. Presignature::issue_partial_signature accepts an attacker-chosen digest without requiring the original message, while set_derivation_path applies a chosen HD path to a presignature. Exploitation requires raw-hash signing or post-presignature HD derivation; the former enables forgery and the latter lowers security to 85 bits.

The record

CVE
CVE-2025-66017
Published
Nov 25, 2025
Updated
Nov 25, 2025
Vendor
Lockness
Product
cggmp21
Classifications
CWE-327, T1565
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 25, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 25, 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.

  1. Affected versionversion=cggmp21 <= 0.6.3
  2. Affected versionversion=cggmp24 = 0.7.0-alpha.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Lockness · cggmp21version=cggmp21 <= 0.6.3; version=cggmp24 = 0.7.0-alpha.1

Published CVSS scores

8.2GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA: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-327Use of a Broken or Risky Cryptographic Algorithm
T1565Data Manipulation

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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