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High 7.1Published May 27, 2026

CVE-2026-47272pam_usb: OTP pad authentication bypass via missing system pad check and uninitialized RNG buffer

Updated under an hour ago ()

Does this affect you?

It affects mcdope pam_usb. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.9.0, the pusb_pad_compare() function in src/pad.c only verified that the user-side pad (~/.pamusb/device.pad) could be read, but did not enforce that the system-side pad (the pad file on the USB device) was also present and readable. If the user-side pad was deleted or unreadable, the function returned a failure that was treated as non-fatal in certain code paths, allowing authentication to succeed without the USB device being verified. A local user can delete their own ~/.pamusb/device.pad to remove the USB device requirement and authenticate without the physical device. This vulnerability is fixed in 0.9.0.

CVSS
7.1 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE)
CWE-287, CWE-908
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Deferred
Record last updated
May 28, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
mcdope pam_usb
mcdope:pam_usb (from the name)
before 0.9.0
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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