Remote authentication via skipped PAM_RHOST check
Published May 27, 2026 · Updated May 27, 2026
Incorrect authorization in mcdope pam_usb before 0.9.1 allows remote attackers to authenticate through XDMCP from a nonlocal session. The pusb_do_auth() function places PAM_RHOST retrieval and rejection inside the deny_remote guard, so setting deny_remote=false skips the hard remote-host check. The flaw does not bypass device authentication; exploitation requires XDMCP exposure, deny_remote=false, a cloned or stolen USB device, and the victim's password.
Summary
What happened
Incorrect authorization in mcdope pam_usb before 0.9.1 allows remote attackers to authenticate through XDMCP from a nonlocal session. The pusb_do_auth() function places PAM_RHOST retrieval and rejection inside the deny_remote guard, so setting deny_remote=false skips the hard remote-host check. The flaw does not bypass device authentication; exploitation requires XDMCP exposure, deny_remote=false, a cloned or stolen USB device, and the victim's password.
The record
- CVE
- CVE-2026-48064
- Published
- May 27, 2026
- Updated
- May 27, 2026
- Vendor
- mcdope
- Product
- pam_usb
- Classifications
- CWE-863, T1133
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 27, 2026CVE publishedPublication date reported by the CVE source.
- May 27, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 0.9.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- XDMCP bypass scenario in issue 348proof of concept · unverified
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Technologies
Your stack
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Your stack
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