CVE-2025-5689Network attack vector

Root-group file access via unset pre-auth GID

Published Jun 16, 2025 · Updated Jun 17, 2025

Privilege misassignment in Canonical authd before 0.5.4 allows remote authenticated users to gain root-group file access during first SSH login. The pre-auth NSS temporary user record leaves its GID unset, so it defaults to GID 0 and makes the new user a root-group member for that session. Exploitation requires PPA installation, a configured Entra ID or Google IAM broker, authd-enabled SSH, an allowed new user, and successful broker authentication; it grants only root-group file permissions, not root privileges.

CVSS severity8.5
High
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege misassignment in Canonical authd before 0.5.4 allows remote authenticated users to gain root-group file access during first SSH login. The pre-auth NSS temporary user record leaves its GID unset, so it defaults to GID 0 and makes the new user a root-group member for that session. Exploitation requires PPA installation, a configured Entra ID or Google IAM broker, authd-enabled SSH, an allowed new user, and successful broker authentication; it grants only root-group file permissions, not root privileges.

The record

CVE
CVE-2025-5689
Published
Jun 16, 2025
Updated
Jun 17, 2025
Vendor
Canonical
Product
authd
Classifications
CWE-269, T1210
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 17, 2025Record 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=0.0.0 <=0.5.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Canonical · authdversion=0.0.0 <=0.5.4

Published CVSS scores

8.5Canonical Ltd.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-269Improper Privilege Management
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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