CVE-2025-5689
Improper Permission Management in SSH Session Handling
A flaw was found in the temporary user record that authd uses in the pre-auth NSS. As a result, a user login for the first time will be considered to be part of the root group in the context of that SSH session.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Improper Permission Management in SSH Session Handling
A flaw was found in the temporary user record that authd uses in the pre-auth NSS. As a result, a user login for the first time will be considered to be part of the root group in the context of that SSH session.
- Record
CVE-2025-5689- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N - Weakness
- CWE-269
- Updated
- 2026-11-02
EUVDEUVD-2025-18385
A flaw was found in the temporary user record that authd uses in the pre-auth NSS. As a result, a user login for the first time will be considered to be part of the root group in the context of that SSH session.
- Record
EUVD-2025-18385- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-g8qw-mgjx-rwjr
New authd users logging in via SSH are members of the root group
Impact
When an authd user logs in via SSH for the first time (meaning they do not yet exist in the authd user database) and successfully authenticates via the configured broker, the user is considered a member of the root group in the context of that SSH session. This situation may allow the user to read and write files that are accessible by the root group, to which they should not have access. The user does not get root privileges or any capabilities beyond the access granted to the root group.
Preconditions under which this vulnerability affects a system
- authd was installed via the PPA.
- An OAuth 2.0 application was registered in Microsoft Entra ID or Google IAM, and the respective authd broker was installed (authd-msentraid or authd-google) and configured.
- sshd was configured to enable SSH access with authd, i.e.:
UsePAM yes KbdInteractiveAuthentication yes - The username is allowed by the
ssh_allowed_suffixesoption in the broker configuriation. - The user is allowed by the
allowed_usersoption in the broker configuration. - The user successfully authenticates via the authd broker (Entra ID or Google IAM).
- The user did not log in locally before.
Patches
Fixed by https://github.com/ubuntu/authd/commit/619ce8e55953b970f1765ddaad565081538151ab
Workarounds
Configure the SSH server to not allow authenticating via authd, for example by setting UsePAM no or KbdInteractiveAuthentication no in the sshd_config (see https://documentation.ubuntu.com/authd/stable/howto/login-ssh/#ssh-configuration).
- Record
GHSA-g8qw-mgjx-rwjr- CVSS 3.1
- 6.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N - Weakness
- CWE-266, CWE-269
- Updated
- 2026-11-02
NVD
A flaw was found in the temporary user record that authd uses in the pre-auth NSS. As a result, a user login for the first time will be considered to be part of the root group in the context of that SSH session.
- Record
CVE-2025-5689- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N - Weakness
- CWE-269
- Updated
- 2026-11-02
OSV
Improper Permission Management in SSH Session Handling
A flaw was found in the temporary user record that authd uses in the pre-auth NSS. As a result, a user login for the first time will be considered to be part of the root group in the context of that SSH session.
- Record
CVE-2025-5689- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-g8qw-mgjx-rwjr
New authd users logging in via SSH are members of the root group
Impact
When an authd user logs in via SSH for the first time (meaning they do not yet exist in the authd user database) and successfully authenticates via the configured broker, the user is considered a member of the root group in the context of that SSH session. This situation may allow the user to read and write files that are accessible by the root group, to which they should not have access. The user does not get root privileges or any capabilities beyond the access granted to the root group.
Preconditions under which this vulnerability affects a system
- authd was installed via the PPA.
- An OAuth 2.0 application was registered in Microsoft Entra ID or Google IAM, and the respective authd broker was installed (authd-msentraid or authd-google) and configured.
- sshd was configured to enable SSH access with authd, i.e.:
UsePAM yes KbdInteractiveAuthentication yes - The username is allowed by the
ssh_allowed_suffixesoption in the broker configuriation. - The user is allowed by the
allowed_usersoption in the broker configuration. - The user successfully authenticates via the authd broker (Entra ID or Google IAM).
- The user did not log in locally before.
Patches
Fixed by https://github.com/ubuntu/authd/commit/619ce8e55953b970f1765ddaad565081538151ab
Workarounds
Configure the SSH server to not allow authenticating via authd, for example by setting UsePAM no or KbdInteractiveAuthentication no in the sshd_config (see https://documentation.ubuntu.com/authd/stable/howto/login-ssh/#ssh-configuration).
- Record
GHSA-g8qw-mgjx-rwjr- CVSS 3.1
- 6.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N - Weakness
- CWE-266, CWE-269
- Updated
- 2026-11-02
OSVGO-2025-3762 No score
New authd users logging in via SSH are members of the root group in github.com/ubuntu/authd
New authd users logging in via SSH are members of the root group in github.com/ubuntu/authd
- Record
GO-2025-3762- Updated
- 2026-11-02
OSVopenSUSE-SU-2025:15405-1 No score
govulncheck-vulndb-0.0.20250730T213748-1.1 on GA media
These are all security issues fixed in the govulncheck-vulndb-0.0.20250730T213748-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2025:15405-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/ubuntu/authdGo |
before 0.5.4 | 0.5.4 |
govulncheck-vulndbopenSUSE:Tumbleweed |
before 0.0.20250730T213748-1.1 | 0.0.20250730T213748-1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-5689 is a high vulnerability (CVSS 8.5) in Canonical Authd, published June 16, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.30%, the 22nd percentile. Fixed in github.com/ubuntu/authd 0.5.4.
References
github.com/ubuntu/authd/security/advisories/GHSA-g8qw-mgjx-rwjr
nvd.nist.gov/vuln/detail/CVE-2025-5689
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suse.com/security/cve/CVE-2024-44905