Science & Tech · Cybersecurity · 1 hr ago
Tailscale prepares patches for flaws that could give attackers root access
Researchers disclosed 11 security flaws in Tailscale software used to connect devices over private networks.
The findings, called Tailworm, affect Tailscale client version 1.104.2 and the self-hosted headscale control server version 0.29.5.
The most serious flaws involve Tailscale SSH, which grants access based on a device and network rules rather than a password or key.
An attacker would first need control of a device that is allowed to connect to a target server, and the attack depends on how access and forwarding are configured.
In lab tests, researchers used the flaws to gain root access, steal device-enrolment keys and move between permitted servers in under a second per step.
The tests were in a lab, and no real-world exploitation was reported; Tailscale also says it does not recommend that everyone disable Tailscale SSH.
Tailscale says fixes are in place for most issues and a patched client is expected after testing, while advising organizations to review SSH rules and turn off forwarding where it is not needed.
Cyberdione Labs researcher Erica Windisch reported 11 vulnerabilities affecting Tailscale client version 1.104.2 and headscale version 0.29.5.
Four of the findings concern Tailscale SSH and could let an attacker with access to one permitted device gain root privileges on reachable servers when forwarding is allowed.
Lab tests showed an automated attack could spread between eligible machines in under a second per step, without user interaction.
The report also describes risks involving app connectors, headscale, the DERP client and Tailscale Serve.
Tailscale said it was working on fixes and advised users to review SSH access policies and disable forwarding where it is not needed.
- Who
- Erica Windisch of Cyberdione Labs reported the flaws. Tailscale is working on fixes.
- What
- A report describes 11 vulnerabilities, including Tailscale SSH flaws that could enable root privilege escalation.
- When
- The findings were published on October 25, 2026. Tailscale discussed fixes on October 26 and 27.
- Where
- The flaws affect Tailscale client version 1.104.2 and headscale version 0.29.5.
- Why
- The SSH flaws could let an attacker who controls a permitted device gain elevated access on reachable servers when forwarding is allowed.
Cyberdione Labs researchers
Tailscale
Disclosure
Cyberdione Labs researchers
Researchers published the report before patches were available, saying rapid awareness could speed remediation.
Tailscale
Tailscale said it was investigating the issues and working on fixes.
Risk and response
Cyberdione Labs researchers
The report describes lab-tested attacks that could spread root access across permitted servers.
Tailscale
Tailscale called the issues serious but said exploitation depends on permissions and configuration, and it was not recommending that everyone disable Tailscale SSH.
Erica Windisch published the Tailworm report on the findings.
Tailscale said it was working on patches, according to the company statements reported by BleepingComputer.
Tailscale said fixes were in place for most issues and it aimed to release a patched client by the end of the day, pending testing.
- Findings
- 11 vulnerabilities, collectively called Tailworm
- Tested Tailscale version
- 1.104.2
- Tested headscale version
- 0.29.5
- Tailscale SSH findings
- Four of the 11 findings concern Tailscale SSH
- Lab spread rate
- Under a second per hop
- Reported researcher
- Erica Windisch of Cyberdione Labs
4 sources
Tailscale Rushes Patches After Uncoordinated Disclosure of ‘Tailworm’ Flaws
Tailscale warns of SSH flaws allowing root privilege escalation
Security researcher identifies potential privilege escalation in Tailscale SSH
Unpatched Tailscale SSH Flaws Could Let a Hacked Device Reach Root on Other Servers
What people are saying
It is the opinion of the researchers that rapid awareness of these flaws will expediate remediation across impacted devices.
the mesh converts one ordinary foothold into fleet-wide privileged access at machine speed.
Most of the issues we’ve identified so far concern what happens after someone has been authorized to connect, particularly how Unix privileges and SSH forwarding are handled. In some cases, a session may be able to do more than the configured local user should be allowed to do.
not recommending that everyone disable Tailscale SSH.