CVE-2026-48981
mediumpriority · track · 0EPSS 0.002 · 5 %ileEUEPSS · scored 2026-10-28
pam_usb provides hardware authentication for Linux using ordinary removable media. In versions prior to 0.9.2, pam_usb calls xmlReadFile() with flags=0 when loading the configuration file, allowing libxml2 to process external entity references (XXE), potentially making outbound network connections or local file reads at XML parse time from the context of the authenticating process. The vulnerability requires the configuration file to contain crafted XML entity references. Since pam_usb.conf is root-owned, direct exploitation requires prior write access to the config, but the defence-in-depth impact is significant given that pam_usb.so runs in setuid contexts (sudo, su). This issue has been fixed in version 0.9.2.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (1)
Products and version ranges known to be affected.
also known as (2)
Other names and identifiers for this entity.
sources
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references (7)
External citations — patches, advisories, analysis.
- https://github.com/mcdope/pam_usb/releasesPatchcnnvd
- https://github.com/mcdope/pam_usb/releases/tag/0.9.2cnnvd
- https://github.com/mcdope/pam_usb/security/advisories/GHSA-96vv-r4wc-28c2cnnvd
- https://github.com/mcdope/pam_usb/releases/tag/0.9.2enisa_euvd
- https://github.com/mcdope/pam_usb/security/advisories/GHSA-96vv-r4wc-28c2enisa_euvd
- https://github.com/mcdope/pam_usb/releases/tag/0.9.2nvd
- https://github.com/mcdope/pam_usb/security/advisories/GHSA-96vv-r4wc-28c2nvd
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