CVE-2023-28436

What it is

Tailscale is software for using Wireguard and multi-factor authentication (MFA). A vulnerability identified in the implementation of Tailscale SSH starting in version 1.34.0 and prior to prior to 1.38.2 in FreeBSD allows commands to be run with a higher privilege group ID than that specified in Tailscale SSH access rules. A difference in the behavior of the FreeBSD `setgroups` system call from POSIX meant that the Tailscale client running on a FreeBSD-based operating system did not appropriately restrict groups on the host when using Tailscale SSH. When accessing a FreeBSD host over Tailscale SSH, the egid of the tailscaled process was used instead of that of the user specified in Tailscale SSH access rules. Tailscale SSH commands may have been run with a higher privilege group ID than that specified in Tailscale SSH access rules if they met all of the following criteria: the destination node was a FreeBSD device with Tailscale SSH enabled; Tailscale SSH access rules permitted access for non-root users; and a non-interactive SSH session was used. Affected users should upgrade to version 1.38.2 to remediate the issue.

At a glance

Exploitability

Can be exploited from the same network segment with an admin-level account, but needs a user to act. High risk of data exposure.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2023-03-23 20:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 05:47 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.5% in the next 30 days (EPSS).
• Severity: 5.7 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2023-03-23 20:15 UTC

Last modified

2026-06-17 05:47 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-269 · Improper privilege management

Record status

Modified

Affected

• Tailscale < 1.38.2

Attack profile CVSS 3.1 · 5.7

Attack vector

Adjacent network

Complexity

Low

Privileges needed

High

User interaction

Required

Scope

Changed

Confidentiality

High

Integrity

None

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2023-28436.md and follow it. Check whether this project is affected by CVE-2023-28436. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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