{"cve":{"cve_id":"CVE-2026-42533","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":0.04059,"epss_percentile":0.89896,"epss_as_of":"2026-08-26","description":"A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and a string expression references the map's regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR.\n\nImpact:\nThis vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only.\n\n\n\n\n Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.","published_at":"2026-07-15T14:33:45.810000Z","last_modified_at":"2026-08-10T15:28:01.940000Z","cvss_v3_score":8.1,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","cvss_v3_severity":"HIGH","cvss_v4_score":9.2,"cvss_v4_vector":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","cvss_v4_severity":"CRITICAL","ssvc_decision":null,"ssvc_exploitation":"none","ssvc_automatable":false,"ssvc_technical_impact":"total","cwes":["CWE-122"],"nvd_references":["https://my.f5.com/manage/s/article/K000162097"],"vuln_status":"Analyzed","trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-07-15T16:34:20.783547Z","updated_at":"2026-08-13T20:20:23.063882Z"},"effective_severity":"CRITICAL","badges":["news"],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"H","value_label":"High"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"H","value_label":"High"},{"metric":"I","name":"Integrity","value":"H","value_label":"High"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":"4.0","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"H","value_label":"High"},{"metric":"AT","name":"Attack Requirements","value":"N","value_label":"None"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"VC","name":"Confidentiality (Vulnerable System)","value":"H","value_label":"High"},{"metric":"VI","name":"Integrity (Vulnerable System)","value":"H","value_label":"High"},{"metric":"VA","name":"Availability (Vulnerable System)","value":"H","value_label":"High"},{"metric":"SC","name":"Confidentiality (Subsequent System)","value":"N","value_label":"None"},{"metric":"SI","name":"Integrity (Subsequent System)","value":"N","value_label":"None"},{"metric":"SA","name":"Availability (Subsequent System)","value":"N","value_label":"None"}]},"affected":[{"vendor_slug":"f5","vendor_name":"F5","product_slug":"nginx-gateway-fabric","product_name":"NGINX Gateway Fabric","version_start":"1.3.0","version_start_inclusive":true,"version_end":"1.6.2","version_end_inclusive":true,"cpe23_uri":"cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:*"},{"vendor_slug":"f5","vendor_name":"F5","product_slug":"nginx-ingress-controller","product_name":"NGINX Ingress Controller","version_start":"3.5.0","version_start_inclusive":true,"version_end":"3.7.2","version_end_inclusive":true,"cpe23_uri":"cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:continuous_releases:*:*:*"},{"vendor_slug":"f5","vendor_name":"F5","product_slug":"nginx-ingress-controller","product_name":"NGINX Ingress Controller","version_start":"2026-lts-r1","version_start_inclusive":true,"version_end":"2026-lts-r4","version_end_inclusive":false,"cpe23_uri":"cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:long-term_support:*:*:*"},{"vendor_slug":"f5","vendor_name":"F5","product_slug":"nginx-ingress-controller","product_name":"NGINX Ingress Controller","version_start":"4.0.0","version_start_inclusive":true,"version_end":"4.0.0","version_end_inclusive":true,"cpe23_uri":"cpe:2.3:a:f5:nginx_ingress_controller:4.0.0:*:*:*:continuous_releases:*:*:*"},{"vendor_slug":"f5","vendor_name":"F5","product_slug":"nginx-ingress-controller","product_name":"NGINX Ingress Controller","version_start":"4.0.1","version_start_inclusive":true,"version_end":"4.0.1","version_end_inclusive":true,"cpe23_uri":"cpe:2.3:a:f5:nginx_ingress_controller:4.0.1:*:*:*:continuous_releases:*:*:*"},{"vendor_slug":"f5","vendor_name":"F5","product_slug":"nginx-open-source","product_name":"NGINX Open Source","version_start":"0.9.6","version_start_inclusive":true,"version_end":"1.30.4","version_end_inclusive":false,"cpe23_uri":"cve5:f5:nginx-open-source:0.9.6:1.30.4"},{"vendor_slug":"f5","vendor_name":"F5","product_slug":"nginx-open-source","product_name":"NGINX Open Source","version_start":"1.31.2","version_start_inclusive":true,"version_end":"1.31.3","version_end_inclusive":false,"cpe23_uri":"cve5:f5:nginx-open-source:1.31.2:1.31.3"},{"vendor_slug":"f5","vendor_name":"F5","product_slug":"nginx-plus","product_name":"NGINX 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Plus","version_start":"r36","version_start_inclusive":true,"version_end":"r36","version_end_inclusive":true,"cpe23_uri":"cpe:2.3:a:f5:nginx_plus:r36:p2:*:*:*:*:*:*"},{"vendor_slug":"f5","vendor_name":"F5","product_slug":"waf","product_name":"waf","version_start":"4.11.0","version_start_inclusive":true,"version_end":"4.16.0","version_end_inclusive":true,"cpe23_uri":"cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:*"}],"exploit_refs":[],"news":[{"id":682,"source":"The Hacker News","url":"https://thehackernews.com/2026/07/critical-nginx-vulnerability-can-crash.html","title":"Critical NGINX Vulnerability Can Crash Workers and May Allow Remote Code Execution","summary":"F5 has shipped fixes for a critical nginx flaw that lets a remote, unauthenticated attacker trigger a heap buffer overflow in the worker process with crafted HTTP requests. CVE-2026-42533 was patched on July 15 in nginx 1.30.4 (stable) and 1.31.3 (mainline), and in NGINX Plus 37.0.3.1; anyone on an earlier build should upgrade.\n\nTriggering it can crash or restart the worker, causing a denial of","thumbnail_url":"https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVv10OUCjBseEZieeN1rxtwm17pPCAoe6OC1jvCTXCumjIImhz5Y08lYWBpSIGBSkDJN-wBcGmUTmPEp8U74bgd2Cv3rwmSmtUDlmOYR7f-0Xs3xL_xkjpkNm8W8vzNvFNfmTNiqs9TNcNmT1bo8xWb9XGzPnuaByxKSl9_eOqg3yDbtAtYh0epFo-4Wg/s1600/nginx-rce-flaw.jpg","author":"info@thehackernews.com (The Hacker News)","published_at":"2026-07-19T20:42:49Z","fetched_at":"2026-07-19T21:38:10.641693Z","trending_score":1.8511752484262136e-6,"cve_ids":["CVE-2026-42533"]}],"references":[{"url":"https://my.f5.com/manage/s/article/K000162097","source_type":"MISC","tags":[]}],"timeline":[{"type":"published","at":"2026-07-15T14:33:45.810000Z","label":"CVE published","source":null},{"type":"first_article","at":"2026-07-19T20:42:49Z","label":"First news coverage","source":"The Hacker News"}]}