CVE-2023-40660VulnerabilityPublished 6 Nov 2023Updated 6 Nov 2025

CVE-2023-40660: Improper Authentication

Source CVE Database V5

Not known to be exploited · CVSS 6.6 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

6.6Medium

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

EPSS: 1.0% chance of exploitation in 30 days – higher than 63% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector: Physical
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

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

Attack Vector: Physical: The attack requires the attacker to physically touch or manipulate the vulnerable component. Physical interaction may be brief or persistent.
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
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 impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 6 Nov 2023
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 2026-10-25.

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 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

AI-suggested

1. Monitor OpenSC project communications and promptly apply patches or updates once they become available to address CVE-2023-40660. 2. Until patched versions are deployed, restrict physical and logical access to systems using OpenSC tokens to trusted personnel only. 3. Implement strict access controls and endpoint security measures to prevent unauthorized local access. 4. Audit and monitor authentication logs for unusual or repeated authentication attempts involving smart cards or tokens. 5. Consider temporarily disabling or limiting the use of smart card authentication for OS logon or screen unlock on high-risk systems. 6. Employ additional layers of security such as hardware security modules (HSMs) or multi-factor authentication methods that do not rely solely on OpenSC tokens. 7. Educate users and administrators about the risk of token misuse and the importance of safeguarding authentication devices. 8. Conduct regular security assessments and penetration tests focusing on smart card authentication mechanisms to detect potential exploitation attempts.

Description

A flaw was found in OpenSC packages that allow a potential PIN bypass. When a token/card is authenticated by one process, it can perform cryptographic operations in other processes when an empty zero-length pin is passed. This issue poses a security risk, particularly for OS logon/screen unlock and for small, permanently connected tokens to computers. Additionally, the token can internally track login status. This flaw allows an attacker to gain unauthorized access, carry out malicious actions, or compromise the system without the user's awareness.

Impact

For European organizations, the impact of CVE-2023-40660 can be substantial, especially in sectors relying heavily on smart card authentication such as government agencies, financial institutions, healthcare, and critical infrastructure operators. Unauthorized cryptographic operations could lead to credential theft, unauthorized access to sensitive systems, data breaches, and potential disruption of services. The ability to bypass PIN authentication undermines trust in multi-factor authentication mechanisms and could facilitate lateral movement within networks. Organizations using OpenSC for OS logon or screen unlock are particularly vulnerable to privilege escalation and persistent compromise. The vulnerability could also affect compliance with European data protection regulations (e.g., GDPR) if exploited to access personal or sensitive data. Given the local access requirement, insider threats or attackers with initial footholds pose the greatest risk. The absence of known exploits in the wild provides a window for proactive mitigation.

References

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