Unpatched Tailscale SSH Flaws Could Let a Hacked Device Reach Root on Other Servers
A single hacked device on a Tailscale network can be used to gain root access to other servers it can reach, according to a security researcher who published the findings this week.
A single hacked device on a Tailscale network can be used to gain root access to other servers it can reach, according to a security researcher who published the findings this week.
The attack requires two things: Tailscale SSH set up to allow port forwarding, and an attacker who already controls one device that the network's access rules permit to connect to the target.
Mike Shaver, the company's vice president of engineering, wrote on Reddit that Tailscale had received the report, had already been looking at the same areas with outside security specialists, and had found issues it is working to fix.
It needs a foothold on one device first, which the report says an attacker can get the usual ways: a vulnerable web application, a poisoned software package, phishing, or stolen login details.
Earlier in 2026, the company fixed several Tailscale SSH and server socket-handling flaws, including one where SSH Unix socket forwarding could reach a privileged socket , in version 1.98.9.
Windisch tested Tailscale version 1.104.2 and headscale version 0.29.5, the self-hosted server some networks use to run Tailscale instead of the company's hosted service, over three days in a lab.
Shaver said the company is still working out which setups are affected, and that it is "not recommending that everyone disable Tailscale SSH." Tailscale SSH does not work like a normal SSH server.
Because of this, the attack needs no stolen passwords or keys.
She said she had also raised concerns about Tailscale's architecture with the company's chief executive earlier, and had publicly posted a file hash and advised users to disable Tailscale SSH.
As of publication, Tailscale had issued no security bulletin , no CVE identifier, and no fixed version.
What happened
A single hacked device on a Tailscale network can be used to gain root access to other servers it can reach, according to a security researcher who published the findings this week.
The attack requires two things: Tailscale SSH set up to allow port forwarding, and an attacker who already controls one device that the network's access rules permit to connect to the target.
What changed
Mike Shaver, the company's vice president of engineering, wrote on Reddit that Tailscale had received the report, had already been looking at the same areas with outside security specialists, and had found issues it is working to fix.
It needs a foothold on one device first, which the report says an attacker can get the usual ways: a vulnerable web application, a poisoned software package, phishing, or stolen login details.
Who is affected
Earlier in 2026, the company fixed several Tailscale SSH and server socket-handling flaws, including one where SSH Unix socket forwarding could reach a privileged socket , in version 1.98.9.
Windisch tested Tailscale version 1.104.2 and headscale version 0.29.5, the self-hosted server some networks use to run Tailscale instead of the company's hosted service, over three days in a lab.
Why it matters
Shaver said the company is still working out which setups are affected, and that it is "not recommending that everyone disable Tailscale SSH." Tailscale SSH does not work like a normal SSH server.
Because of this, the attack needs no stolen passwords or keys.
Technical details
She said she had also raised concerns about Tailscale's architecture with the company's chief executive earlier, and had publicly posted a file hash and advised users to disable Tailscale SSH.
As of publication, Tailscale had issued no security bulletin , no CVE identifier, and no fixed version.
Using standard SSH port forwarding, an ordinary session caused the root-level Tailscale process to connect to a system socket that only root should access, and the test gained root and read the system password file almost immediately, without administrator rights.
Response
Because there is no patch, the available steps are changes to how Tailscale SSH and related features are set up.
Rather than checking a connecting user's password or key, it identifies the device, and a single access rule decides whether that device may open an SSH session to a target.
What security teams should do
The report says every SSH grant there should therefore be treated as giving root on the target; tailscale also suggests enabling SSH check mode, which adds a login step before a session starts, and enabling automatic updates.
Attribution
The Hacker News: A single hacked device on a Tailscale network can be used to gain root access to other servers it can reach, according to a security researcher who published the findings this week.
What to watch next
Watch for updated vendor guidance and fixed-version details.