Tailworm: researcher drops 11 Tailscale and headscale flaws; Tailscale 1.104.4 fixes the SSH forwarding root escalation
Published Sources: pwn.watch
What is affected, what to do
Erica Windisch of Cyberdione Labs published Tailworm, 11 lab-reproduced findings in Tailscale v1.104.2 and headscale v0.29.5 without coordinated disclosure. The main one: with Tailscale SSH enabled, unix-socket port forwarding runs as root, so anyone with one approved device and an SSH rule can reach root on the target and capture enrollment keys.
The available sources name no fixed version. Check the vendor guidance in the references below.
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Metrics
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CVSS v3
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Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 30.00 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
Erica Windisch of Cyberdione Labs published Tailworm, 11 lab-reproduced findings in Tailscale v1.104.2 and headscale v0.29.5 without coordinated disclosure. The main one: with Tailscale SSH enabled, unix-socket port forwarding runs as root, so anyone with one approved device and an SSH rule can reach root on the target and capture enrollment keys. Others cover experimental app connectors bypassing ACLs (cloud metadata, internal LANs), a tailscale serve forward to the local API, and headscale/DERP memory exhaustion. Tailscale confirmed the SSH issues as serious privilege-escalation bugs and on Oct 28 released Tailscale 1.104.4 with bulletins TS-2026-014 (SSH unix-socket forwarding to root-only sockets such as the Docker socket or local API), TS-2026-015 (SSH session memory exhaustion), TS-2026-016 (serve unix backends reaching privileged sockets) and TS-2026-017 (HTTP/2 serve capability mix-up). Upgrade to 1.104.4 or newer; the bulletins do not cover the app-connector or headscale findings. It is lateral movement from a foothold, not internet RCE.
Source: pwn.watch