{"id":"CVE-2026-118965","kind":"vulnerability","aliases":["CVE-2026-118965"],"related":[],"title":"Checkmk: path traversal lets a remote site write files and run code","description":"Path traversal in the discovered host label synchronization in Checkmk <2.5.0p19, <2.4.0p40 and 2.3.0 (EOL) allows an attacker in control of a remote site in a distributed monitoring setup to write arbitrary files on the central site and thereby execute code as the central site user.","summary":"Checkmk's discovered host label synchronization has a path traversal flaw. An attacker who controls a remote site in a distributed monitoring setup can write arbitrary files on the central site and execute code as the central site user.","severity":"critical","cvss":9.4,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["checkmk","distributed-monitoring","infrastructure","self-hosted"],"not_affected_if":["fixed-version-installed","single-site-only"],"how_to_check":"- Check the installed Checkmk version on the central site with `omd version` and compare it to the fixed versions below.\n- Check whether any remote sites are connected to the central site in a distributed setup.","fix":"- Checkmk `2.5.0p19` or later\n- Checkmk `2.4.0p40` or later\n- Checkmk 2.3.0 is end of life; the sources give no fix for it, so move to a supported release.","status":"open","published_at":"2026-11-11T11:17:13+00:00","first_seen_at":"2026-11-11T11:26:55+00:00","triaged_at":"2026-11-11T11:27:28+00:00","updated_at":"2026-11-11T11:27:28+00:00","category":"infrastructure","confidence":0.7,"triage":{"at":"2026-11-11T11:27:28Z","model":"claude-haiku-5-5","output":{"fix":"- Checkmk `2.5.0p19` or later\n- Checkmk `2.4.0p40` or later\n- Checkmk 2.3.0 is end of life; the sources give no fix for it, so move to a supported release.","reach":"network","title":"Checkmk: path traversal lets a remote site write files and run code","impact":"high","summary":"Checkmk's discovered host label synchronization has a path traversal flaw. An attacker who controls a remote site in a distributed monitoring setup can write arbitrary files on the central site and execute code as the central site user.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["checkmk","self-hosted","distributed-monitoring"],"confidence":0.7,"fix_status":"available","needs_auth":"yes","worst_case":"code runs as the central site user; monitoring data readable","analyst_note":"Confirm the 2.3.0 EOL status and whether it has a patched release.","how_to_check":"- Check the installed Checkmk version on the central site with `omd version` and compare it to the fixed versions below.\n- Check whether any remote sites are connected to the central site in a distributed setup.","plain_action":"","product_name":"","needs_analyst":false,"not_affected_if":["single-site-only","fixed-version-installed"],"who_is_affected":"Exposure requires a distributed monitoring setup where a remote site is connected to a central Checkmk site. The attacker must control a remote site, so single-site installations without remote sites are less exposed. Teams running only standalone sites can deprioritize, but should still confirm the version.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"yes","severity_if_unknown":"critical"},"cost_usd":0.000744,"input_tokens":4574,"output_tokens":574,"severity_before":"critical"},"analyst_status":null,"analyst_note":null,"search":"'-118965':15A,18A '-2026':14A,17A '2.3.0':81C '2.4.0':78C '2.5.0':76C 'allow':83C 'arbitrari':52B,99C 'attack':39B,85C 'central':56B,63B,103C,111C 'checkmk':1A,19B,27B,75C 'code':12A,60B,108C 'control':41B,87C 'cve':13A,16A 'discov':29B,70C 'distribut':21B,47B,94C 'distributed-monitor':20B 'eol':82C 'execut':59B,107C 'file':9A,53B,100C 'flaw':37B 'host':26B,30B,71C 'infrastructur':23B 'label':31B,72C 'let':4A 'monitor':22B,48B,95C 'p19':77C 'p40':79C 'path':2A,35B,66C 'remot':6A,43B,90C 'run':11A 'self':25B 'self-host':24B 'setup':49B,96C 'site':7A,44B,57B,64B,91C,104C,112C 'synchron':32B,73C 'therebi':106C 'travers':3A,36B,67C 'user':65B,113C 'write':8A,51B,98C","nicknames":[],"mitigations":[],"who_affected":"Exposure requires a distributed monitoring setup where a remote site is connected to a central Checkmk site. The attacker must control a remote site, so single-site installations without remote sites are less exposed. Teams running only standalone sites can deprioritize, but should still confirm the version.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["checkmk","critical","distributedmonitoring","infrastructure","selfhosted"],"campaign_type":null,"search_a":"'-118965':15A,18A '-2026':14A,17A 'checkmk':1A 'code':12A 'cve':13A,16A 'file':9A 'let':4A 'path':2A 'remot':6A 'run':11A 'site':7A 'travers':3A 'write':8A","search_b":"'arbitrari':52B 'attack':39B 'central':56B,63B 'checkmk':19B,27B 'code':60B 'control':41B 'discov':29B 'distribut':21B,47B 'distributed-monitor':20B 'execut':59B 'file':53B 'flaw':37B 'host':26B,30B 'infrastructur':23B 'label':31B 'monitor':22B,48B 'path':35B 'remot':43B 'self':25B 'self-host':24B 'setup':49B 'site':44B,57B,64B 'synchron':32B 'travers':36B 'user':65B 'write':51B","search_c":"'2.3.0':81C '2.4.0':78C '2.5.0':76C 'allow':83C 'arbitrari':99C 'attack':85C 'central':103C,111C 'checkmk':75C 'code':108C 'control':87C 'discov':70C 'distribut':94C 'eol':82C 'execut':107C 'file':100C 'host':71C 'label':72C 'monitor':95C 'p19':77C 'p40':79C 'path':66C 'remot':90C 'setup':96C 'site':91C,104C,112C 'synchron':73C 'therebi':106C 'travers':67C 'user':113C 'write':98C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-11T11:17:13+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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","cvss_by":"security@checkmk.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-118965","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118965","severity":null,"published_at":"2026-11-11T11:17:13+00:00","modified_at":"2026-11-11T11:17:13+00:00","first_seen_at":"2026-11-11T11:26:55+00:00","fetched_at":"2026-11-11T11:26:55+00:00","note":null}],"documents":[],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}