CVE-2026-48983

One-time pad exposure via directory symlink race

Published Jun 18, 2026 · Updated Jun 18, 2026

TOCTOU race in pad directory creation in mcdope pam_usb before 0.9.2 allows local users to expose or disrupt one-time pads. In src/pad.c, separate lstat() existence checks and mkdir() calls leave per-device and per-user paths replaceable with symlinks before pad files are written. Exploitation requires low-privileged local access and winning the timing window; success exposes future pad values or interrupts authentication.

CVSS severity5.8
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

TOCTOU race in pad directory creation in mcdope pam_usb before 0.9.2 allows local users to expose or disrupt one-time pads. In src/pad.c, separate lstat() existence checks and mkdir() calls leave per-device and per-user paths replaceable with symlinks before pad files are written. Exploitation requires low-privileged local access and winning the timing window; success exposes future pad values or interrupts authentication.

The record

CVE
CVE-2026-48983
Published
Jun 18, 2026
Updated
Jun 18, 2026
Vendor
mcdope
Product
pam_usb
Classifications
CWE-367, T1552.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 18, 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=< 0.9.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

mcdope · pam_usbversion=< 0.9.2

Published CVSS scores

5.8GitHub, Inc.CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L

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-367Time-of-check Time-of-use (TOCTOU) Race Condition
T1552.001Unsecured Credentials: Credentials In Files

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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