CVE-2025-24032: opensc pam_pkcs11 Improper Authentication

Vulnerability summary

CVE-2025-24032 is a critical (CVSS 9.2) Improper Authentication vulnerability in opensc pam_pkcs11. EPSS estimates a 0.71% chance of exploitation in the next 30 days, higher than 52.7% of scored vulnerabilities.

Timeline

1. 10-02-2025
   PublishedVulnerability first disclosed.
2. 21-05-2025
   Last modifiedVulnerability information updated.

Description

PAM-PKCS#11 is a Linux-PAM login module that allows a X.509 certificate based user login. Prior to version 0.6.13, if cert_policy is set to none (the default value), then pam_pkcs11 will only check if the user is capable of logging into the token. An attacker may create a different token with the user's public data (e.g. the user's certificate) and a PIN known to the attacker. If no signature with the private key is required, then the attacker may now login as user with that created token. The default to *not* check the private key's signature has been changed with commit commi6638576892b59a99389043c90a1e7dd4d783b921, so that all versions starting with pam_pkcs11-0.6.0 should be affected. As a workaround, in `pam_pkcs11.conf`, set at least `cert_policy = signature;`.

• CWE-287Improper AuthenticationWhen an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.