Vulnerability · Published May 27, 2026 · Assigned by GitHub_M

CVE-2026-47273pam_usb: XPath injection via PAM-supplied identifiers in pam_usb configuration queries

Medium 6.5

In plain English

A medium-severity security flaw in pam_usb from mcdope. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 20% of all known vulnerabilities).

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.3%top 80.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
mcdope	pam_usb	< 0.9.0

Weakness: CWE-91 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N

References

https://github.com/mcdope/pam_usb/security/advisories/GHSA-vfj3-5h5v-6g93 x_refsource_CONFIRM
https://github.com/mcdope/pam_usb/pull/311 x_refsource_MISC
https://github.com/mcdope/pam_usb/commit/721fed08a3596cb5b4671ad702f8fdc12dcc7420 x_refsource_MISC