Critical Security Update for pam-u2f: Addressing Vulnerability DSA-5853-1
Summary
DSA-5853-1: pam-u2f - security update. Affects pam-u2f versions < 1.1.0-1.1+deb12u1. Fixed in 1.1.0-1.1+deb12u1. How to fix ↓
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Background
pam-u2f is a PAM (Pluggable Authentication Module) that enables two-factor authentication using U2F (Universal 2nd Factor) devices. It enhances security by requiring a physical token in addition to a password for user authentication. This package is widely used in systems requiring robust security measures. However, it has been identified to have a security vulnerability that could potentially compromise user authentication processes.
Vulnerability Detail
The vulnerability identified as CVE-2025-23013 in pam-u2f allows an attacker to bypass the two-factor authentication mechanism under certain conditions. This could lead to unauthorized access to systems relying on this authentication method. The issue originates from improper handling of authentication requests, which may allow attackers to exploit the flaw and gain access without the required physical token. The ramifications of this vulnerability are significant, as it undermines the core purpose of two-factor authentication, exposing sensitive data and systems to potential breaches.
How To Fix
Minimum fixed version
1.1.0-1.1+deb12u1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade pam-u2fTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, you may consider disabling the pam-u2f module until the package is updated. This can be done by commenting out the relevant line in your PAM configuration file (usually located at /etc/pam.d/common-auth) that references pam-u2f. However, this is not recommended as it reduces the security of your authentication process.
Conclusion
The pam-u2f package has a critical vulnerability (CVE-2025-23013) that needs immediate attention. Users are advised to update to the patched version to ensure the security of their authentication processes. Temporary workarounds exist, but they compromise security and should be avoided if possible.
See every vulnerability recorded for pam-u2f →
FAQ
pam-u2f is a PAM module that provides two-factor authentication using U2F devices, enhancing security by requiring a physical token.
CVE-2025-23013 refers to a specific vulnerability in the pam-u2f package that allows attackers to bypass two-factor authentication.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
Not updating pam-u2f exposes your system to potential unauthorized access, as the vulnerability allows attackers to bypass the two-factor authentication mechanism.
Yes, Vulert can monitor and alert you in real-time for open-source vulnerabilities using just a manifest file like package-lock.json.
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