mcdope pam_usb up to 0.9.0 on Linux PAM Service pusb_do_auth authorization

Summaryinfo

A vulnerability was found in mcdope pam_usb up to 0.9.0 on Linux. It has been classified as problematic. Impacted is the function pusb_do_auth of the component PAM Service. Performing a manipulation results in authorization. This vulnerability is known as CVE-2026-48064. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as problematic has been found in mcdope pam_usb up to 0.9.0 on Linux. This affects the function pusb_do_auth of the component PAM Service. The manipulation with an unknown input leads to a authorization vulnerability. CWE is classifying the issue as CWE-863. The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.9.1, when a PAM service is configured with deny_remote=false in pam_usb (commonly done for display managers such as gdm-password or lightdm to bypass process/TTY heuristics for local sessions), the PAM_RHOST check in pusb_do_auth() is also skipped. PAM_RHOST is set by remote daemons (sshd, XDMCP servers) to identify the remote client address. Because the check is gated inside if (opts.deny_remote), a genuine remote XDMCP connection reaches the USB device authentication step instead of being rejected. This vulnerability is fixed in 0.9.1.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-48064 since 05/20/2026. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available.

Upgrading to version 0.9.1 eliminates this vulnerability.

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Productinfo

Vendor

• mcdope

Name

• pam_usb

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7
• 0.8
• 0.9.0

Website

• Product: https://github.com/mcdope/pam_usb/

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