{"id":"CVE-2026-103593","kind":"vulnerability","aliases":["CVE-2026-103593"],"related":[],"title":"WatchGuard Fireware OS: logging service overflow lets rogue log server run code","description":"A stack-based buffer overflow vulnerability in the Fireware OS logging service allows a network-adjacent attacker who can impersonate or intercept traffic to the configured log server to execute arbitrary code with root privileges by presenting a specially crafted certificate.","summary":"A stack-based buffer overflow in the Fireware OS logging service is triggered when a crafted certificate is presented by a log server the device connects to. An attacker who can impersonate or intercept traffic to that log server can run arbitrary code as root on the appliance.","severity":"high","cvss":7.1,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["firewall","fireware-os","infrastructure","network-appliance","watchguard"],"not_affected_if":["no-remote-log-server"],"how_to_check":"- unknown","fix":"- unknown","status":"open","published_at":"2026-10-27T16:17:28+00:00","first_seen_at":"2026-10-27T16:33:06+00:00","triaged_at":"2026-10-27T16:34:20+00:00","updated_at":"2026-10-27T16:34:20+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-10-27T16:34:20Z","model":"claude-haiku-5-5","output":{"fix":"- unknown","reach":"network","title":"WatchGuard Fireware OS: logging service overflow lets rogue log server run code","impact":"high","summary":"A stack-based buffer overflow in the Fireware OS logging service is triggered when a crafted certificate is presented by a log server the device connects to. An attacker who can impersonate or intercept traffic to that log server can run arbitrary code as root on the appliance.","category":"infrastructure","nicknames":[],"who_cares":["watchguard","fireware-os","firewall","network-appliance"],"confidence":0.5,"needs_auth":"no","worst_case":"Attacker runs code as root on the firewall appliance","analyst_note":"Find WatchGuard's advisory and the affected and fixed Fireware OS versions, plus the log-server TLS configuration that triggers the flaw.","how_to_check":"- unknown","needs_analyst":true,"not_affected_if":["no-remote-log-server"],"who_is_affected":"Organizations running WatchGuard Fireware OS firewalls that send logs to a configured log server over a network path an attacker could intercept or impersonate. Devices that do not forward logs to a remote server, or whose log traffic stays on a trusted, protected path, are less exposed; the sources do not name affected versions.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.000568,"input_tokens":3305,"output_tokens":476,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-103593':15A,18A '-2026':14A,17A 'adjac':94C 'allow':90C 'applianc':26B,76B 'arbitrari':70B,109C 'attack':57B,95C 'base':31B,80C 'buffer':32B,81C 'certif':45B,119C 'code':12A,71B,110C 'configur':104C 'connect':54B 'craft':44B,118C 'cve':13A,16A 'devic':53B 'execut':108C 'firewal':19B 'firewar':2A,21B,36B,86C 'fireware-o':20B 'imperson':60B,98C 'infrastructur':23B 'intercept':62B,100C 'let':7A 'log':4A,9A,38B,50B,66B,88C,105C 'network':25B,93C 'network-adjac':92C 'network-appli':24B 'os':3A,22B,37B,87C 'overflow':6A,33B,82C 'present':47B,115C 'privileg':113C 'rogu':8A 'root':73B,112C 'run':11A,69B 'server':10A,51B,67B,106C 'servic':5A,39B,89C 'special':117C 'stack':30B,79C 'stack-bas':29B,78C 'traffic':63B,101C 'trigger':41B 'vulner':83C 'watchguard':1A,27B","nicknames":[],"mitigations":[],"who_affected":"Organizations running WatchGuard Fireware OS firewalls that send logs to a configured log server over a network path an attacker could intercept or impersonate. Devices that do not forward logs to a remote server, or whose log traffic stays on a trusted, protected path, are less exposed; the sources do not name affected versions.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T16:17:28+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/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":"5d1c2695-1a31-4499-88ae-e847036fd7e3","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-103593","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-103593","severity":null,"published_at":"2026-10-27T16:17:28+00:00","modified_at":"2026-10-27T16:17:28+00:00","first_seen_at":"2026-10-27T16:33:06+00:00","fetched_at":"2026-10-27T16:33:06+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"}