CVE-2026-47272 (GCVE-0-2026-47272)

Vulnerability from cvelistv5 – Published: 2026-05-27 20:06 – Updated: 2026-05-28 12:53
VLAI
Title
pam_usb: OTP pad authentication bypass via missing system pad check and uninitialized RNG buffer
Summary
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.
Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CWE
  • CWE-287 - Improper Authentication
  • CWE-908 - Use of Uninitialized Resource
Assigner
References
Impacted products
Vendor Product Version
mcdope pam_usb Affected: < 0.9.0
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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