Tailscale is racing to patch 11 security flaws disclosed publicly without a coordinated release process, including weaknesses in Tailscale SSH that could allow an authorized user to escape the permissions of their configured account and potentially gain root privileges.
Researcher Erica Windisch of Cyberdione Labs published the findings under the name Tailworm on October 25 after auditing Tailscale 1.104.2 and the self-hosted headscale control server version 0.29.5. The report covers Tailscale SSH, the Serve and app connector features, the DERP relay client and headscale. Tailscale said it received the report and is investigating the issues with outside security specialists.
The most serious reported weakness involves Unix-socket forwarding through Tailscale SSH. According to the researcher’s technical report, an attacker must already be authorized to connect over Tailscale SSH, but forwarding operations handled by the privileged tailscaled process may reach root-only sockets or be exploited through a race condition. That could enable access to sensitive files, credential material or root-level command execution on a target server. Tailscale describes the potential impact more cautiously, saying exploitation depends on the user or device permissions, system configuration and other conditions.
As of October 27, Tailscale had not published CVE identifiers, CVSS scores or a final security advisory for the findings. The company’s investigation and remediation update said engineers had implemented fixes for most of the issues and were testing a patched client release targeted for the end of Tuesday. The update did not identify a confirmed exploitation campaign, threat actor or public exploit beyond the researcher’s disclosure, and Tailscale has not said that the flaws are being exploited in the wild.
Until the fixed release is available, Tailscale recommends restricting Tailscale SSH policies to necessary users and devices, reviewing access to sensitive systems and disabling forwarding where it is not required. Administrators can set TS_SSH_DISABLE_FORWARDING=1 in the tailscaled service environment and restart the service, a measure the company says mitigates several of the more serious findings without disabling Tailscale SSH entirely. Customers should monitor the Tailscale security bulletins and apply the patched client as soon as it is released. [30]
