CVE-2026-47273
CVE-2026-47273 is a medium-severity vulnerability with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-91.
Key facts
- Severity: Medium (CVSS 3.x base score 6.5)
- EPSS exploit prediction: 0% (19th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-32652
- Weakness: CWE-91
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-47273?
- 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.
- How severe is CVE-2026-47273?
- CVE-2026-47273 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.
- Is CVE-2026-47273 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-47273?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-47273 have an EU (EUVD) identifier?
- Yes. CVE-2026-47273 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-32652.
- When was CVE-2026-47273 published?
- CVE-2026-47273 was published on 2026-05-27 and last updated on 2026-06-17.
References
- https://github.com/mcdope/pam_usb/commit/721fed08a3596cb5b4671ad702f8fdc12dcc7420
- https://github.com/mcdope/pam_usb/pull/311
- https://github.com/mcdope/pam_usb/security/advisories/GHSA-vfj3-5h5v-6g93
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