VulnerabilityPublished 25 Nov 2025

CVE-2025-66016: LFDT-Lockness cggmp21 · Insufficient Verification of Data Authenticity

Affects LFDT-Lockness cggmp21Source CVE Database V5

Not known to be exploited · CVSS 9.3 Critical : upgrade to 0.6.3 as a priority.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 4.0 base score

9.3Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.6.3

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: High
Vulnerable system integrity: High
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: High: There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Vulnerable system integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the vulnerable system. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the vulnerable system.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade lfdt-lockness/cggmp21 to 0.6.3.

Affected software

Product	Affected	Fixed in
GitHublfdt-lockness/cggmp21`pkg:github/lfdt-lockness/cggmp21`Other threats	Affected <0.6.3	Fixed in 0.6.3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate this vulnerability, European organizations should immediately upgrade all instances of the LFDT-Lockness cggmp21 product to version 0.6.3 or later, with a strong recommendation to adopt version 0.7.0-alpha.2, which includes additional security checks. Organizations should audit their cryptographic implementations to identify any use of vulnerable versions and verify that no unauthorized key reconstruction has occurred. Implement strict access controls and monitoring around signing operations to detect anomalous behavior indicative of an insider threat. Where possible, employ hardware-based security modules that enforce cryptographic operations and prevent key extraction. Additionally, organizations should review their multi-party signing protocols to ensure no single participant can compromise the entire key. Regularly update threat intelligence and vulnerability management processes to detect and respond to emerging exploits. Finally, consider engaging with vendors and cryptographic experts to validate the security posture of threshold signature deployments and apply best practices for key management and protocol verification.

Description

CVE-2025-66016 is a critical vulnerability in the LFDT-Lockness cggmp21 product, specifically versions prior to 0.6.3. The flaw stems from insufficient verification of data authenticity in the zero-knowledge (ZK) proof within the CGGMP24 ECDSA threshold signature scheme (TSS) protocol. This missing check allows a single malicious signer to reconstruct the entire private key, compromising the cryptographic security of the system. The vulnerability has a CVSS 4.0 score of 9.3, indicating high exploitability and severe impact without requiring authentication or user interaction. Although no known exploits are currently reported in the wild, the risk is significant due to the nature of the cryptographic key compromise. Mitigation requires upgrading to version 0.

Impact

The potential impact on European organizations is severe due to the critical nature of the vulnerability. Organizations using cggmp21 in cryptographic operations risk full private key compromise, which can lead to unauthorized transaction signing, data integrity violations, and loss of trust in digital signatures. This is especially impactful for sectors such as banking, finance, telecommunications, government, and critical infrastructure, where threshold signatures are used to secure sensitive operations and multi-party authorization. The compromise of private keys could facilitate fraud, unauthorized access, and disruption of services. Additionally, the breach of cryptographic keys may have regulatory implications under GDPR and other European cybersecurity laws, potentially resulting in fines and reputational damage. The lack of known exploits in the wild does not diminish the urgency, as the vulnerability is straightforward to exploit by a malicious insider or attacker with access to the signing process. The scope of affected systems includes any cryptographic infrastructure leveraging vulnerable versions of cggmp21, which may be embedded in hardware security modules (HSMs), blockchain platforms, or secure communication systems.

CWE-345Insufficient Verification of Data Authenticity (opens in a new tab)
Class weaknessOWASP Top 10 A08:2025: Software or Data Integrity Failures (opens in a new tab)
The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
OWASP Cheat Sheets
XML Security (opens in a new tab)
REST Security (opens in a new tab)
JSON Web Token for Java (opens in a new tab)
REST Assessment (opens in a new tab)
Cross-Site Request Forgery Prevention (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.2 (opens in a new tab)
V3.5.3 (opens in a new tab)
V13.2.6 (opens in a new tab)
Attack patterns
JSON Hijacking (aka JavaScript Hijacking) (opens in a new tab)
Cache Poisoning (opens in a new tab)
DNS Cache Poisoning (opens in a new tab)
Spoofing of UDDI/ebXML Messages (opens in a new tab)
Application API Message Manipulation via Man-in-the-Middle (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 2 Dec 2025, 20:49 UTC

WeaknessesCWE-345

Technical details

References

Community reviews

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