{"id":"CVE-2026-56434","state":"PUBLISHED","title":"NGINX ngx_http_ssi_module vulnerability","description":"NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_ssi_module module. This vulnerability may exist when the Server-Side Includes (SSI), proxy_pass, and proxy_buffering off directives are configured. With this configuration, an unauthenticated attacker with man-in-the-middle (MITM) ability to control responses from an upstream server may be able to cause a use-after-free in the NGINX worker process. This issue may lead to limited modification of memory or a restart of the NGINX worker process.\n\nImpact:\nThis vulnerability may allow remote attackers to have limited control to modify memory contents or restart the NGINX worker process. There is no control plane exposure; this is a data plane issue only.\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated.","publishedAt":"2026-07-15T14:33:46.142Z","updatedAt":"2026-07-15T18:10:54.402Z","severity":{"score":8.3,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N","source":"f5"},"assigner":"f5","products":["F5 NGINX Plus","F5 NGINX Open Source"],"affected":[{"vendor":"F5","product":"NGINX Plus","defaultStatus":"unknown","versions":[{"version":"37.0.0.1","status":"affected","lessThan":"37.0.3.1","versionType":"custom"},{"version":"R36","status":"affected","lessThan":"R36 P7","versionType":"custom"},{"version":"R33","status":"affected","lessThan":"*","versionType":"custom"}],"modules":["ngx_http_ssi_module"]},{"vendor":"F5","product":"NGINX Open Source","defaultStatus":"unknown","versions":[{"version":"1.31.2","status":"affected","lessThan":"1.31.3","versionType":"custom"},{"version":"0.8.11","status":"affected","lessThan":"1.30.4","versionType":"custom"}],"modules":["ngx_http_ssi_module"]}],"references":["https://my.f5.com/manage/s/article/K000162098"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/56xxx/CVE-2026-56434.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-56434","state":"PUBLISHED","datePublished":"2026-07-15T14:33:46.142Z","dateUpdated":"2026-07-15T18:10:54.402Z","assignerShortName":"f5","assignerOrgId":"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab","dateReserved":"2026-07-08T15:49:43.050Z"},"containers":{"cna":{"title":"NGINX ngx_http_ssi_module vulnerability","descriptions":[{"lang":"en","value":"NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_ssi_module module. This vulnerability may exist when the Server-Side Includes (SSI), proxy_pass, and proxy_buffering off directives are configured. With this configuration, an unauthenticated attacker with man-in-the-middle (MITM) ability to control responses from an upstream server may be able to cause a use-after-free in the NGINX worker process. This issue may lead to limited modification of memory or a restart of the NGINX worker process.\n\nImpact:\nThis vulnerability may allow remote attackers to have limited control to modify memory contents or restart the NGINX worker process. There is no control plane exposure; this is a data plane issue only.\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated."}],"affected":[{"vendor":"F5","product":"NGINX Plus","defaultStatus":"unknown","versions":[{"version":"37.0.0.1","status":"affected","lessThan":"37.0.3.1","versionType":"custom"},{"version":"R36","status":"affected","lessThan":"R36 P7","versionType":"custom"},{"version":"R33","status":"affected","lessThan":"*","versionType":"custom"}],"modules":["ngx_http_ssi_module"]},{"vendor":"F5","product":"NGINX Open Source","defaultStatus":"unknown","versions":[{"version":"1.31.2","status":"affected","lessThan":"1.31.3","versionType":"custom"},{"version":"0.8.11","status":"affected","lessThan":"1.30.4","versionType":"custom"}],"modules":["ngx_http_ssi_module"]}],"references":[{"url":"https://my.f5.com/manage/s/article/K000162098","tags":["vendor-advisory","patch"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"HIGH","baseSeverity":"MEDIUM","baseScore":6.5,"vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"version":"4.0","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","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":"HIGH","baseScore":8.3,"vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","lang":"en","description":"CWE-416 Use After Free","type":"CWE"}]}],"providerMetadata":{"shortName":"f5","orgId":"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab","dateUpdated":"2026-07-15T18:10:54.402Z"},"datePublic":"2026-07-15T14:00:00.000Z","credits":[{"lang":"en","value":"F5 acknowledges p4p3r(@P4P3R-HAK)\" of \"싸이버원(CYBERONE) 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":"2026-07-15T15:38:13.231118Z","id":"CVE-2026-56434","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-15T15:38:21.639Z"}}]}}}