CVE-2026-48064 (GCVE-0-2026-48064)
Vulnerability from cvelistv5 – Published: 2026-05-27 19:59 – Updated: 2026-06-02 17:40
VLAI
EPSS
VEX
Title
pam_usb: PAM_RHOST check skipped when deny_remote=false allows XDMCP authentication bypass
Summary
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.
Severity
8.1 (High)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-02 17:40 UTC
CWE
- CWE-863 - Incorrect Authorization
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/mcdope/pam_usb/security/adviso… | x_refsource_CONFIRM |
| https://github.com/mcdope/pam_usb/issues/348 | x_refsource_MISC |
Impacted products
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Browse all ATT&CK techniques and the vulnerabilities related to each.
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