CVE-2026-47269Network attack vector

SSH authentication bypass via partial IPv6 address check

Published May 27, 2026 · Updated May 27, 2026

Authentication bypass in mcdope pam_usb before 0.9.0 allows remote attackers to authenticate over SSH with a registered USB device. The deny_remote check in src/local.c tests only ut_addr_v6[0], so IPv4-mapped IPv6 sessions with the address in later words skip remote detection and are treated as local. Exploitation requires physical access to a registered USB device and an SSH service whose IPv6 wildcard listener records IPv4 clients as mapped IPv6 addresses; successful access carries the device owner's account privileges.

CVSS severity7.4
High
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in mcdope pam_usb before 0.9.0 allows remote attackers to authenticate over SSH with a registered USB device. The deny_remote check in src/local.c tests only ut_addr_v6[0], so IPv4-mapped IPv6 sessions with the address in later words skip remote detection and are treated as local. Exploitation requires physical access to a registered USB device and an SSH service whose IPv6 wildcard listener records IPv4 clients as mapped IPv6 addresses; successful access carries the device owner's account privileges.

The record

CVE
CVE-2026-47269
Published
May 27, 2026
Updated
May 27, 2026
Vendor
mcdope
Product
pam_usb
Classifications
CWE-284, T1078
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. 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.

  1. Affected versionversion=< 0.9.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

mcdope · pam_usbversion=< 0.9.0

Published CVSS scores

7.4GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1078Valid Accounts

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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