{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","favicon":"https://feed.craftedsignal.io/favicon-32x32.png","feed_url":"https://feed.craftedsignal.io/cpes/cpe2.3af5nginx_javascript/feed.json","home_page_url":"https://feed.craftedsignal.io/","icon":"https://feed.craftedsignal.io/apple-touch-icon.png","items":[{"_cs_actors":[],"_cs_cpes":["cpe:2.3:a:f5:nginx_javascript:*:*:*:*:*:*:*:*"],"_cs_cves":[{"cvss":8.2,"id":"CVE-2026-18329"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["NGINX JavaScript","QuickJS"],"_cs_severities":["high"],"_cs_tags":[],"_cs_type":"advisory","_cs_vendors":["F5"],"content_html":"\u003cp\u003eThe NGINX JavaScript (njs) and QuickJS (qjs) engines contain a vulnerability involving the js_access handler during asynchronous request body processing. When an exception occurs during the asynchronous access-control evaluation phase - specifically before the handler can return an explicit access denial - the engine may fail open. This misconfiguration in the access validation logic permits the request to proceed to downstream resources despite failing security checks.\u003c/p\u003e\n\u003cp\u003eAn unauthenticated remote attacker can exploit this condition by sending a crafted HTTP request designed to trigger an error within the access-control JavaScript logic. This results in an authorization bypass, potentially allowing access to protected endpoints that should have been restricted. This vulnerability exists within the data plane, impacting any application relying on the njs or qjs access control handlers for security enforcement.\u003c/p\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows unauthenticated remote attackers to bypass security controls defined within the js_access handler. This can result in unauthorized access to sensitive application data or protected administrative functions. As this is a data plane issue affecting request processing, it does not involve exposure of the server control plane but directly undermines the security posture of the web application.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eIdentify all instances of NGINX utilizing the \u003ccode\u003ejs_access\u003c/code\u003e handler for security controls.\u003c/li\u003e\n\u003cli\u003eAudit JavaScript access control logic to ensure that error conditions do not result in a default-allow state.\u003c/li\u003e\n\u003cli\u003eMonitor web server error logs for unexpected exceptions occurring within JavaScript access handlers, which may indicate exploitation attempts.\u003c/li\u003e\n\u003cli\u003eApply patches provided by the software vendor once available for NGINX and affected distributions.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-09-02T17:15:05Z","date_published":"2026-09-02T17:15:05Z","id":"https://feed.craftedsignal.io/briefs/2026-09-nginx-auth-bypass/","summary":"An authentication bypass flaw in NGINX JavaScript (njs) and QuickJS (qjs) engines allows unauthenticated attackers to trigger a fail-open state in access control logic, potentially granting unauthorized access to protected resources.","title":"Authentication Bypass in NGINX JavaScript and QuickJS Engines","url":"https://feed.craftedsignal.io/briefs/2026-09-nginx-auth-bypass/"}],"language":"en","title":"CraftedSignal Threat Feed - Cpe:2.3:a:f5:nginx_javascript:*:*:*:*:*:*:*:*","version":"https://jsonfeed.org/version/1.1"}