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

Vulnerability from cvelistv5 – Published: 2026-05-27 20:06 – Updated: 2026-05-27 20:06
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.
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
Create a notification for this product.
Show details on NVD website

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "pam_usb",
          "vendor": "mcdope",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.9.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "NONE",
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-287",
              "description": "CWE-287: Improper Authentication",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-908",
              "description": "CWE-908: Use of Uninitialized Resource",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-27T20:06:15.388Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/mcdope/pam_usb/security/advisories/GHSA-vx6f-rrqr-j87c",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/mcdope/pam_usb/security/advisories/GHSA-vx6f-rrqr-j87c"
        }
      ],
      "source": {
        "advisory": "GHSA-vx6f-rrqr-j87c",
        "discovery": "UNKNOWN"
      },
      "title": "pam_usb: OTP pad authentication bypass via missing system pad check and uninitialized RNG buffer"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-47272",
    "datePublished": "2026-05-27T20:06:15.388Z",
    "dateReserved": "2026-05-18T23:03:37.230Z",
    "dateUpdated": "2026-05-27T20:06:15.388Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-47272\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-05-27T20:16:39.747\",\"lastModified\":\"2026-05-27T20:16:39.747\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"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.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N\",\"baseScore\":7.1,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":1.8,\"impactScore\":5.2}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-287\"},{\"lang\":\"en\",\"value\":\"CWE-908\"}]}],\"references\":[{\"url\":\"https://github.com/mcdope/pam_usb/security/advisories/GHSA-vx6f-rrqr-j87c\",\"source\":\"security-advisories@github.com\"}]}}"
  }
}


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