CVE-2026-47270

Authentication policy bypass via shared strtok state

Published May 27, 2026 · Updated May 27, 2026

Race condition in pam_usb before 0.9.0 allows local users to corrupt deny_remote decisions during concurrent PAM requests. Three remote-session helpers share strtok state, while pusb_tmux_get_client_tty tokenizes the live TMUX environment value in place. Exploitation requires overlapping authentications in one multithreaded PAM host and can incorrectly classify a remote or local session.

CVSS severity6.3
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in pam_usb before 0.9.0 allows local users to corrupt deny_remote decisions during concurrent PAM requests. Three remote-session helpers share strtok state, while pusb_tmux_get_client_tty tokenizes the live TMUX environment value in place. Exploitation requires overlapping authentications in one multithreaded PAM host and can incorrectly classify a remote or local session.

The record

CVE
CVE-2026-47270
Published
May 27, 2026
Updated
May 27, 2026
Vendor
mcdope
Product
pam_usb
Classifications
CWE-362, T1068
Attack vector
local
Privileges
authenticated

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 vectorlocal
Required privilegesauthenticated

What is affected?

mcdope · pam_usbversion=< 0.9.0

Published CVSS scores

6.3GitHubCVSS:3.1/AV:L/AC:H/PR:L/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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1068Exploitation for Privilege Escalation

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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