{"id":"CVE-2026-8711","state":"PUBLISHED","title":"NGINX JavaScript vulnerability","description":"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.","publishedAt":"2026-05-19T14:04:18.860Z","updatedAt":"2026-05-21T18:29:16.674Z","severity":{"score":9.2,"label":"Critical","version":"4.0","vector":"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","source":"f5"},"assigner":"f5","products":["F5 NGINX JavaScript"],"affected":[{"vendor":"F5","product":"NGINX JavaScript","defaultStatus":"unknown","versions":[{"version":"0.9.4","status":"affected","lessThan":"0.9.9","versionType":"custom"}],"modules":["ngx_http_js_module"]}],"references":["https://my.f5.com/manage/s/article/K000161307"],"weaknesses":["CWE-122"],"ingestedAt":"2026-10-29T20:13:26.108Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/8xxx/CVE-2026-8711.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-8711","state":"PUBLISHED","datePublished":"2026-05-19T14:04:18.860Z","dateUpdated":"2026-05-21T18:29:16.674Z","assignerShortName":"f5","assignerOrgId":"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab","dateReserved":"2026-05-15T20:10:29.764Z"},"containers":{"cna":{"title":"NGINX JavaScript vulnerability","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."}],"affected":[{"vendor":"F5","product":"NGINX JavaScript","defaultStatus":"unknown","versions":[{"version":"0.9.4","status":"affected","lessThan":"0.9.9","versionType":"custom"}],"modules":["ngx_http_js_module"]}],"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"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-122","lang":"en","description":"CWE-122 Heap-based Buffer Overflow","type":"CWE"}]}],"providerMetadata":{"shortName":"f5","orgId":"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab","dateUpdated":"2026-05-21T18:29:16.674Z"},"datePublic":"2026-05-19T14:00:00.000Z","tags":["x_F5"],"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":[{"title":"CISA ADP Vulnrichment","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"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-05-20T03:55:39.626Z"}}]}}}