CVE-2025-24032 PAM-PKCS#11 vulnerable to authentication bypass with default value for `cert_policy` (`none`)
Attackers can bypass authentication in PAM-PKCS#11 by creating a token with the user's public certificate, allowing unauthorized login as the victim.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-24032?
CVE-2025-24032 is a critical authentication bypass vulnerability in OpenSC pam_pkcs11, published on 10 Feb 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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;`.
Weakness: CWE-287
Which versions are affected by CVE-2025-24032?
How do I fix CVE-2025-24032?
Upgrade to a fixed version.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2025-24032 being exploited?
There is no known exploitation of CVE-2025-24032 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2025-24032, DLA-4058-1, GHSA-8r8p-7mgp-vf56, UBUNTU-CVE-2025-24032.