{"id":"CVE-2025-66969","kind":"vulnerability","aliases":["CVE-2025-66969"],"related":[],"title":"OpenModSim: integer overflow lets a crafted input crash it","description":"Integer overflow in OpenModSim (<=1.11.0), leading to denial of service","summary":"OpenModSim, a Modbus simulator, has an integer overflow in versions up to 1.11.0. Sending crafted input can cause a denial of service.","severity":"high","cvss":7.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["industrial","modbus","openmodsim","other"],"not_affected_if":["unknown"],"how_to_check":"- Check the installed OpenModSim version against `1.11.0` (unknown how the version is reported by the sources)\n- Confirm whether the simulator is reachable from untrusted networks (unknown from the sources)","fix":"- Move to a release newer than `1.11.0` once the vendor ships one (unknown from the sources)","status":"open","published_at":"2026-10-16T19:16:57+00:00","first_seen_at":"2026-10-23T21:57:14+00:00","triaged_at":"2026-10-25T03:24:56+00:00","updated_at":"2026-10-25T03:24:56+00:00","category":"other","confidence":0.4,"triage":{"at":"2026-10-25T03:24:56Z","model":"claude-haiku-5-5","output":{"fix":"- Move to a release newer than `1.11.0` once the vendor ships one (unknown from the sources)","reach":"unknown","title":"OpenModSim: integer overflow lets a crafted input crash it","impact":"low","summary":"OpenModSim, a Modbus simulator, has an integer overflow in versions up to 1.11.0. Sending crafted input can cause a denial of service.","category":"other","nicknames":[],"who_cares":["openmodsim","modbus","industrial"],"confidence":0.4,"needs_auth":"unknown","worst_case":"Simulator process crashes or hangs, denying service","analyst_note":"Check the NVD entry and the OpenModSim project for the affected code path, the triggering input, and a fixed version.","how_to_check":"- Check the installed OpenModSim version against `1.11.0` (unknown how the version is reported by the sources)\n- Confirm whether the simulator is reachable from untrusted networks (unknown from the sources)","needs_analyst":true,"not_affected_if":["unknown"],"who_is_affected":"Teams running OpenModSim 1.11.0 or older, most likely in industrial or test lab setups where it simulates Modbus devices. Exposure depends on whether the simulator listens on a network the attacker can reach; unknown from the sources.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000568,"input_tokens":3237,"output_tokens":488,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-2025':10A,13A '-66969':11A,14A '1.11.0':30B,44C 'caus':35B 'craft':6A,32B 'crash':8A 'cve':9A,12A 'denial':37B,47C 'industri':15B 'input':7A,33B 'integ':2A,24B,40C 'lead':45C 'let':4A 'modbus':16B,20B 'openmodsim':1A,17B,18B,43C 'overflow':3A,25B,41C 'send':31B 'servic':39B,49C 'simul':21B 'version':27B","nicknames":[],"mitigations":[],"who_affected":"Teams running OpenModSim 1.11.0 or older, most likely in industrial or test lab setups where it simulates Modbus devices. Exposure depends on whether the simulator listens on a network the attacker can reach; unknown from the sources.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-16T19:16:57+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvss_by":"134c704f-9b21-4f2e-91b3-4a467353bcc0","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2025-66969","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-66969","severity":null,"published_at":"2026-10-16T19:16:57+00:00","modified_at":"2026-10-21T02:17:02+00:00","first_seen_at":"2026-10-23T21:57:14+00:00","fetched_at":"2026-10-23T22:28:55+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}