Vulnerability in cline (CVE-2026-44211)
Summary
Vulnerability in cline (CVE-2026-44211). Successful exploitation can lead to full system takeover. Exploitable via kanban.
Original description
The description as published by the source.
Summary
The kanban npm package (used by the cline CLI) starts a WebSocket server on 127.0.0.1:3484 with no Origin header validation. Any website a developer visits can silently connect to the kanban server via WebSocket and:
- Leak sensitive data in real-time: workspace filesystem paths, task titles/descriptions, git branch info, AI agent chat messages
- Hijack running AI agent terminals by injecting arbitrary prompts into the agent's input, leading to remote code execution
- Kill running agent tasks by terminating active sessions via the control WebSocket
WebSocket connections are not subject to CORS restrictions. The browser sends them freely to localhost regardless of the page's origin. The kanban server accepts all connections without checking the Origin header.
Affected Component
- Package:
kanbanon npm (https://www.npmjs.com/package/kanban) - Repository: https://github.com/cline/kanban
- Tested version: 0.1.59
- Installed via:
clineCLI (cline --kanbanor defaultclinecommand) - Endpoints:
ws://127.0.0.1:3484/api/runtime/ws,ws://127.0.0.1:3484/api/terminal/io,ws://127.0.0.1:3484/api/terminal/control
Root Cause
Three WebSocket endpoints are exposed without authentication or Origin validation.
1. Runtime state stream (no Origin check on upgrade)
server.on("upgrade", (request, socket, head) => {
if (normalizeRequestPath(requestUrl.pathname) !== "/api/runtime/ws") {
return;
}
// No Origin hea…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-44211 has been found in cline.
Attackers can target a specific entry point like kanban over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 9.6/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "cline CVE-2026-44211" on the vendor's site.
CVE-2026-44211 (cline) — CWE-306 / CVSS v3 9.6
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: kanban / cline / task_sessions_updated
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-306) exists in cline. Attackers reach the vulnerable code path via kanban without authentication.
Check the vendor advisory for the affected versions of cline. Attack surface: kanban / cline / task_sessions_updated.
Severity: Critical (CVSS 9.6/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'cline' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'cline' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
clineを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- exploit github.com
- package github.com
- web github.com