CVE-2023-40661VulnerabilityPublished 6 Nov 2023Updated 6 Nov 2025

CVE-2023-40661: OpenSC · Memory Buffer Overflow

Affects OpenSCSource CVE Database V5

Not known to be exploited · CVSS 5.4 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

5.4Medium

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

EPSS: 1.3% chance of exploitation in 30 days – higher than 70% 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:L/I:L/A:H

Attack Vector: Physical
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: Low
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: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on 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 2026-10-26.

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

Affected software

Product	Affected	Fixed in
GitHubopensc/OpenSC`pkg:github/opensc/OpenSC`Other threats	Affected =0	Fixed in–

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

AI-suggested

To mitigate CVE-2023-40661, European organizations should implement strict physical security controls to prevent unauthorized access to systems handling smart card enrollment. This includes securing workstations, using locked rooms or cabinets, and monitoring access logs. Organizations should validate the authenticity of USB devices and smart cards before enrollment, potentially using hardware-based device attestation or whitelisting known devices. Applying vendor patches or updates for OpenSC as soon as they become available is critical. Until patches are deployed, consider disabling or restricting the use of pkcs15-init enrollment processes or isolating enrollment systems from general network access. Employ endpoint security solutions capable of detecting anomalous USB device behavior. Additionally, conduct regular audits of cryptographic key and certificate integrity post-enrollment to detect any unauthorized changes. Training staff on the risks of physical device manipulation and enforcing strict enrollment procedures will further reduce risk.

Description

Several memory vulnerabilities were identified within the OpenSC packages, particularly in the card enrollment process using pkcs15-init when a user or administrator enrolls cards. To take advantage of these flaws, an attacker must have physical access to the computer system and employ a custom-crafted USB device or smart card to manipulate responses to APDUs. This manipulation can potentially allow compromise key generation, certificate loading, and other card management operations during enrollment.

Impact

For European organizations, the impact of CVE-2023-40661 is significant in sectors relying heavily on smart card-based authentication and cryptographic operations, such as government agencies, financial institutions, and critical infrastructure operators. Successful exploitation could lead to unauthorized manipulation of cryptographic keys and certificates, undermining the trustworthiness of authentication and encryption mechanisms. This could result in data breaches, unauthorized access, and disruption of secure communications. The requirement for physical access limits the attack scope but raises concerns for environments with shared or poorly secured workstations. The compromise of card enrollment processes may also affect compliance with regulations like GDPR and eIDAS, which mandate strong identity and access management controls. Additionally, the availability impact could disrupt operational workflows dependent on smart card authentication, causing downtime or service degradation.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Nov 2025, 23:43 UTC

Technical details

References

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