{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-8711","assignerOrgId":"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab","state":"PUBLISHED","assignerShortName":"f5","dateReserved":"2026-05-15T20:10:29.764Z","datePublished":"2026-05-19T14:04:18.860Z","dateUpdated":"2026-05-21T18:29:16.674Z"},"containers":{"cna":{"providerMetadata":{"orgId":"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab","shortName":"f5","dateUpdated":"2026-05-21T18:29:16.674Z"},"title":"NGINX JavaScript vulnerability","datePublic":"2026-05-19T14:00:00.000Z","problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-122","description":"CWE-122 Heap-based Buffer Overflow","type":"CWE"}]}],"affected":[{"vendor":"F5","product":"NGINX JavaScript","modules":["ngx_http_js_module"],"versions":[{"status":"affected","version":"0.9.4","lessThan":"0.9.9","versionType":"custom"}],"defaultStatus":"unknown"}],"descriptions":[{"lang":"en","value":"NGINX JavaScript has a vulnerability when the js_fetch_proxy directive is configured with at least one client-controlled NGINX variable (for example, $http_*, $arg_*, $cookie_*) and a location invoking the ngx.fetch() operation from NGINX JavaScript. An unauthenticated attacker can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. \n\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated.","supportingMedia":[{"type":"text/html","base64":false,"value":"<span style=\"background-color: rgb(255, 255, 255);\">NGINX JavaScript has a vulnerability when the </span><strong>js_fetch_proxy</strong><span style=\"background-color: rgb(255, 255, 255);\">&nbsp;directive is configured with at least one client-controlled NGINX variable (for example, </span><strong>$http_*</strong><span style=\"background-color: rgb(255, 255, 255);\">, </span><strong>$arg_*</strong><span style=\"background-color: rgb(255, 255, 255);\">, </span><strong>$cookie_*</strong><span style=\"background-color: rgb(255, 255, 255);\">) and a location invoking the ngx.fetch() operation from NGINX JavaScript. An unauthenticated attacker 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.</span> \n\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated."}]}],"tags":["x_F5"],"references":[{"url":"https://my.f5.com/manage/s/article/K000161307","tags":["vendor-advisory"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","baseSeverity":"HIGH","baseScore":8.1,"vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"version":"4.0","attackVector":"NETWORK","attackComplexity":"HIGH","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subAvailabilityImpact":"NONE","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","baseSeverity":"CRITICAL","baseScore":9.2,"vectorString":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}}],"credits":[{"lang":"en","value":"\"F5 acknowledges udolemi (S2W) for bringing this issue to our attention and following the highest standards of coordinated disclosure.\"","type":"reporter"}],"source":{"discovery":"EXTERNAL"},"x_generator":{"engine":"F5 SIRTBot v1.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-19T00:00:00+00:00","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3","id":"CVE-2026-8711"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-05-20T03:55:39.626Z"}}]}}