{"id":"CVE-2026-121638","kind":"vulnerability","aliases":["CVE-2026-121638"],"related":[],"title":"WatchGuard AuthPoint Gateway before 7.6.0: improper certificate validation allows man-in-the-middle attacks","description":"An Improper Certificate Validation vulnerability in WatchGuard AuthPoint Gateway allows an attacker with an on-path network position to intercept and modify communications between the AuthPoint Gateway and local authentication providers.","summary":"WatchGuard AuthPoint Gateway does not properly validate certificates when talking to local authentication providers. An attacker on the network path can intercept and modify that traffic.","severity":"critical","cvss":9.1,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"AuthPoint Gateway","fixed":["7.6.0"],"affected":">= 1.0, < 7.6.0","ecosystem":"vendor"}],"ecosystems":[],"tags":["authentication","authpoint","infrastructure","mfa","mitm","self-hosted","watchguard","windows"],"not_affected_if":["no-authpoint-gateway"],"how_to_check":"Find your installed WatchGuard AuthPoint Gateway version (Windows Server host running the Gateway service; also shown in the AuthPoint management console under Gateways). Any version from 1.0 up to but not including 7.6.0 is affected. Per-CVE advisory text was not readable; only the vendor listing's version range was.","fix":"Upgrade AuthPoint Gateway to 7.6.0 or later (released 29 Oct 2026).","status":"open","published_at":"2026-11-04T15:17:42+00:00","first_seen_at":"2026-11-04T15:27:30+00:00","triaged_at":"2026-11-04T15:28:20+00:00","updated_at":"2026-11-04T15:30:10+00:00","category":"infrastructure","confidence":0.8,"triage":{"at":"2026-11-04T15:28:20Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"WatchGuard AuthPoint Gateway: certificate checks missing, traffic to auth providers interceptable","impact":"high","summary":"WatchGuard AuthPoint Gateway does not properly validate certificates when talking to local authentication providers. An attacker on the network path can intercept and modify that traffic.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["watchguard","authpoint","authentication","mfa"],"confidence":0.5,"fix_status":"unknown","needs_auth":"unknown","worst_case":"attacker intercepts and alters authentication traffic between gateway and providers","analyst_note":"Find the WatchGuard advisory and the affected and fixed AuthPoint Gateway versions; the NVD entry at https://nvd.nist.gov/vuln/detail/CVE-2026-121638 gives no version ranges.","how_to_check":"- Confirm whether your environment runs WatchGuard AuthPoint Gateway (unknown whether the sources list affected versions)\n- Review the gateway's connections to local authentication providers for network paths an attacker could reach","plain_action":"","needs_analyst":true,"not_affected_if":["no-authpoint-gateway"],"who_is_affected":"Organizations running the WatchGuard AuthPoint Gateway that connect it to local authentication providers over a network an attacker could sit on. The sources do not list affected versions or specific configurations, so the exact exposure is unknown.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"critical"},"cost_usd":0.00069,"input_tokens":4108,"output_tokens":559,"severity_before":"critical"},"analyst_status":"done","analyst_note":"Find the WatchGuard advisory and the affected and fixed AuthPoint Gateway versions; the NVD entry at https://nvd.nist.gov/vuln/detail/CVE-2026-121638 gives no version ranges.","search":"'-121638':18A,21A '-2026':17A,20A '7.6.0':5A 'allow':9A,69C 'attack':15A,49B,71C 'authent':24B,46B,90C 'authpoint':2A,22A,25B,35B,67C,86C 'certif':7A,41B,62C 'communic':83C 'cve':16A,19A 'gateway':3A,23A,36B,68C,87C 'host':31B 'improp':6A,61C 'infrastructur':26B 'intercept':55B,80C 'local':45B,89C 'man':11A 'man-in-the-middl':10A 'mfa':27B 'middl':14A 'mitm':28B 'modifi':57B,82C 'network':52B,77C 'on-path':74C 'path':53B,76C 'posit':78C 'proper':39B 'provid':47B,91C 'self':30B 'self-host':29B 'talk':43B 'traffic':59B 'valid':8A,40B,63C 'vulner':64C 'watchguard':1A,32B,34B,66C 'window':33B","nicknames":[],"mitigations":[],"who_affected":"Anyone running the self-installed WatchGuard AuthPoint Gateway (the Windows Server application that serves RADIUS, ADFS and LDAP for AuthPoint MFA) on a version below 7.6.0. Per the vendor listing, a network attacker can intercept the Gateway's connections because certificates are not properly validated. Teams not running the Gateway can skip it.","tier":"B","verified":{"fix":{"at":"2026-11-04T15:30:10Z","by":"analyst","doc":"https://www.watchguard.com/support/release-notes/cloud/Content/en-US/AuthPoint/EN_release-notes_authpoint.html","run_id":1677},"products":{"at":"2026-11-04T15:30:10Z","by":"analyst","doc":"https://www.watchguard.com/support/release-notes/cloud/Content/en-US/AuthPoint/EN_release-notes_authpoint.html","run_id":1677}},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":["authpointgateway","gateway"],"ptokens":["authpoint","gateway"],"labels":["authentication","authpoint","critical","infrastructure","mfa","mitm","selfhosted","watchguard","windows"],"campaign_type":null,"first_public_at":"2026-11-04T15:17:42+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/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","cvss_by":"5d1c2695-1a31-4499-88ae-e847036fd7e3","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-121638","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121638","severity":null,"published_at":"2026-11-04T15:17:42+00:00","modified_at":"2026-11-04T15:17:42+00:00","first_seen_at":"2026-11-04T15:27:30+00:00","fetched_at":"2026-11-04T15:27:30+00:00","note":null},{"source":"analyst","external_id":"CVE-2026-121638:1677","url":null,"severity":null,"published_at":"2026-11-04T15:30:10+00:00","modified_at":"2026-11-04T15:30:10+00:00","first_seen_at":"2026-11-04T15:30:10+00:00","fetched_at":"2026-11-04T15:30:10+00:00","note":"WatchGuard PSIRT listing (CVSS 9.1, published 2026-11-04) gives affected >=1.0,<7.6.0, fixed 7.6.0; release notes confirm Gateway 7.6.0 on 29 Oct 2026 (they say only 'resolved a security vulnerability', not tied to this CVE). Per-CVE advisory page not retrievable, so no detail on attack preconditions; no exploitation info seen. Siblings: CVE-2026-121637/39/40 share the same range."}],"documents":[{"id":6985,"url":"https://psirt.watchguard.com/","title":"WatchGuard Security Advisories (PSIRT listing)","kind":"advisory","source":"analyst","publisher":null,"text":"WatchGuard PSIRT index row (psirt.watchguard.com, fetched 2026-10-27):\nSeverity 7.2 | CVE-2026-90464 Fireware OS Missing Command Validation allows Authenticated Arbitrary File Modification as Root | Affected: Default >= 2025.1, < 2026.4; >= 12.0, < 12.12.4. T15/T35 >= 12.0, < 12.5.22. Fixed: >= 2026.4, >= 12.12.4; T15/T35 >= 12.5.22 | Published 2026-10-27\n","published_at":null,"relation":"advisory","confidence":null,"note":null},{"id":67995,"url":"https://www.watchguard.com/support/release-notes/cloud/Content/en-US/AuthPoint/EN_release-notes_authpoint.html","title":"AuthPoint release notes (Gateway 7.6.0)","kind":"release","source":"analyst","publisher":null,"text":null,"published_at":null,"relation":"fix","confidence":null,"note":null}],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}