mcdope pam_usb up to 0.8.x on Linux Removable Media /etc/pamusb.conf xml injection

Summaryinfo

A vulnerability, which was classified as critical, has been found in mcdope pam_usb up to 0.8.x on Linux. Affected by this issue is some unknown functionality of the file /etc/pamusb.conf of the component Removable Media Handler. The manipulation leads to xml injection. This vulnerability is documented as CVE-2026-47273. The attack can be initiated remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in mcdope pam_usb up to 0.8.x on Linux and classified as critical. This issue affects an unknown functionality of the file /etc/pamusb.conf of the component Removable Media Handler. The manipulation with an unknown input leads to a xml injection vulnerability. Using CWE to declare the problem leads to CWE-91. The product does not properly neutralize special elements that are used in XML, allowing attackers to modify the syntax, content, or commands of the XML before it is processed by an end system. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.9.0, pam_usb builds XPath expressions from user-supplied identifiers (PAM username, service name) and device-supplied identifiers (USB device serial, model, vendor) to query /etc/pamusb.conf. These identifiers were not validated for XPath metacharacters, allowing injection of arbitrary XPath predicates. This vulnerability is fixed in 0.9.0.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-47273 since 05/19/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1505 for this issue.

Upgrading to version 0.9.0 eliminates this vulnerability. Applying the patch 721fed08a3596cb5b4671ad702f8fdc12dcc7420 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• mcdope

Name

• pam_usb

Version

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

License

• open-source

Website

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

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CPE 2.2info

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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