{"api_version":"1","generated_at":"2026-04-23T01:33:28+00:00","cve":"CVE-2026-27651","urls":{"html":"https://cve.report/CVE-2026-27651","api":"https://cve.report/api/cve/CVE-2026-27651.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-27651","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-27651"},"summary":{"title":"NGINX ngx_mail_auth_http_module vulnerability","description":"When the ngx_mail_auth_http_module module is enabled on NGINX Plus or NGINX Open Source, undisclosed requests can cause worker processes to terminate. This issue may occur when (1) CRAM-MD5 or APOP authentication is enabled, and (2) the authentication server permits retry by returning the Auth-Wait response header. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.","state":"PUBLISHED","assigner":"f5","published_at":"2026-03-24 15:16:32","updated_at":"2026-03-30 14:02:05"},"problem_types":["CWE-476","CWE-476 CWE-476 NULL Pointer Dereference"],"metrics":[{"version":"4.0","source":"f5sirt@f5.com","type":"Secondary","score":"8.7","severity":"HIGH","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","data":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","baseScore":8.7,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}},{"version":"4.0","source":"CNA","type":"CVSS","score":"8.7","severity":"HIGH","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","data":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":8.7,"baseSeverity":"HIGH","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"}},{"version":"3.1","source":"f5sirt@f5.com","type":"Primary","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"CVSS","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://my.f5.com/manage/s/article/K000160383","name":"https://my.f5.com/manage/s/article/K000160383","refsource":"f5sirt@f5.com","tags":["Vendor Advisory"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-27651","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27651","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"F5","product":"NGINX Open Source","version":"affected 1.29.0 1.29.7 semver","platforms":[]},{"source":"CNA","vendor":"F5","product":"NGINX Open Source","version":"affected 0.5.15 1.28.3 semver","platforms":[]},{"source":"CNA","vendor":"F5","product":"NGINX Plus","version":"affected R36 R36 P3 custom","platforms":[]},{"source":"CNA","vendor":"F5","product":"NGINX Plus","version":"affected R35 R35 P2 custom","platforms":[]},{"source":"CNA","vendor":"F5","product":"NGINX Plus","version":"affected R34 * custom","platforms":[]},{"source":"CNA","vendor":"F5","product":"NGINX Plus","version":"affected R33 * custom","platforms":[]},{"source":"CNA","vendor":"F5","product":"NGINX Plus","version":"affected R32 R32 P5 custom","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"F5 acknowledges Arkadi Vainbrand for bringing this issue to our attention and following the highest standards of coordinated disclosure.","lang":"en"}],"nvd_cpes":[{"cve_year":"2026","cve_id":"27651","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"f5","cpe5":"nginx_open_source","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2026","cve_id":"27651","vulnerable":"1","versionEndIncluding":"0.9.7","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"f5","cpe5":"nginx_open_source","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-27651","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-03-24T15:02:03.137056Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-03-24T15:14:13.220Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"defaultStatus":"unknown","modules":["ngx_mail_auth_http_module"],"product":"NGINX Open Source","vendor":"F5","versions":[{"lessThan":"1.29.7","status":"affected","version":"1.29.0","versionType":"semver"},{"lessThan":"1.28.3","status":"affected","version":"0.5.15","versionType":"semver"}]},{"defaultStatus":"unaffected","modules":["ngx_mail_auth_http_module"],"product":"NGINX Plus","vendor":"F5","versions":[{"lessThan":"R36 P3","status":"affected","version":"R36","versionType":"custom"},{"lessThan":"R35 P2","status":"affected","version":"R35","versionType":"custom"},{"lessThan":"*","status":"affected","version":"R34","versionType":"custom"},{"lessThan":"*","status":"affected","version":"R33","versionType":"custom"},{"lessThan":"R32 P5","status":"affected","version":"R32","versionType":"custom"}]}],"credits":[{"lang":"en","type":"reporter","value":"F5 acknowledges Arkadi Vainbrand for bringing this issue to our attention and following the highest standards of coordinated disclosure."}],"datePublic":"2026-03-24T14:00:00.000Z","descriptions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<span style=\"background-color: rgb(255, 255, 255);\">When the </span><strong>ngx_mail_auth_http_module</strong><span style=\"background-color: rgb(255, 255, 255);\">&nbsp;module is enabled on NGINX Plus or NGINX Open Source, undisclosed requests can cause worker processes to terminate. This issue may occur when (1) CRAM-MD5 or APOP authentication is enabled, and (2) the authentication server permits retry by returning the Auth-Wait response header.</span> Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated."}],"value":"When the ngx_mail_auth_http_module module is enabled on NGINX Plus or NGINX Open Source, undisclosed requests can cause worker processes to terminate. This issue may occur when (1) CRAM-MD5 or APOP authentication is enabled, and (2) the authentication server permits retry by returning the Auth-Wait response header. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated."}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]},{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":8.7,"baseSeverity":"HIGH","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-476","description":"CWE-476 NULL Pointer Dereference","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-03-24T14:22:35.756Z","orgId":"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab","shortName":"f5"},"references":[{"tags":["vendor-advisory"],"url":"https://my.f5.com/manage/s/article/K000160383"}],"source":{"discovery":"EXTERNAL"},"title":"NGINX ngx_mail_auth_http_module vulnerability","x_generator":{"engine":"F5 SIRTBot v1.0"}}},"cveMetadata":{"assignerOrgId":"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab","assignerShortName":"f5","cveId":"CVE-2026-27651","datePublished":"2026-03-24T14:13:27.295Z","dateReserved":"2026-03-18T16:06:38.454Z","dateUpdated":"2026-03-24T15:14:13.220Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-03-24 15:16:32","lastModifiedDate":"2026-03-30 14:02:05","problem_types":["CWE-476","CWE-476 CWE-476 NULL Pointer Dereference"],"metrics":{"cvssMetricV40":[{"source":"f5sirt@f5.com","type":"Secondary","cvssData":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","baseScore":8.7,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}],"cvssMetricV31":[{"source":"f5sirt@f5.com","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":3.6}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:*","versionStartIncluding":"0.5.15","versionEndIncluding":"0.9.7","matchCriteriaId":"89573E06-4D65-4D4A-B9CD-7FD8AF637342"},{"vulnerable":true,"criteria":"cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:*","versionStartIncluding":"1.0.0","versionEndExcluding":"1.28.3","matchCriteriaId":"0E8049B1-4C36-4711-BB99-2721CF67FF81"},{"vulnerable":true,"criteria":"cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:*","versionStartIncluding":"1.29.0","versionEndExcluding":"1.29.7","matchCriteriaId":"C0EFE28B-E8E5-464E-B407-96436CA87C8E"},{"vulnerable":true,"criteria":"cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:*","versionStartIncluding":"r33","versionEndExcluding":"r35","matchCriteriaId":"E7600A88-7651-4D8E-A04A-3AA81C850CC5"},{"vulnerable":true,"criteria":"cpe:2.3:a:f5:nginx_plus:r32:-:*:*:*:*:*:*","matchCriteriaId":"36C4308E-651E-437C-84E7-10C542E3ADC2"},{"vulnerable":true,"criteria":"cpe:2.3:a:f5:nginx_plus:r32:p1:*:*:*:*:*:*","matchCriteriaId":"FA913184-EAAD-409E-99C6-AB979DAA93F3"},{"vulnerable":true,"criteria":"cpe:2.3:a:f5:nginx_plus:r32:p2:*:*:*:*:*:*","matchCriteriaId":"782DF180-1101-4D6A-A1D7-8DADBAF6D9D3"},{"vulnerable":true,"criteria":"cpe:2.3:a:f5:nginx_plus:r32:p3:*:*:*:*:*:*","matchCriteriaId":"FB0B11F2-4748-492B-9906-F8C4C5EAFF12"},{"vulnerable":true,"criteria":"cpe:2.3:a:f5:nginx_plus:r32:p4:*:*:*:*:*:*","matchCriteriaId":"86B53968-1CCA-4CF3-8454-BB92EF64D10E"},{"vulnerable":true,"criteria":"cpe:2.3:a:f5:nginx_plus:r35:-:*:*:*:*:*:*","matchCriteriaId":"5D5FFD66-35C3-41AD-BD77-510E34A3AC6F"},{"vulnerable":true,"criteria":"cpe:2.3:a:f5:nginx_plus:r35:p1:*:*:*:*:*:*","matchCriteriaId":"4958360C-7993-4C82-8685-202D4940CE01"},{"vulnerable":true,"criteria":"cpe:2.3:a:f5:nginx_plus:r36:-:*:*:*:*:*:*","matchCriteriaId":"E7E5F940-048A-446F-9A1E-074612CEA1AC"},{"vulnerable":true,"criteria":"cpe:2.3:a:f5:nginx_plus:r36:p1:*:*:*:*:*:*","matchCriteriaId":"7993A0FB-BE7E-4634-BF7F-FDEE3582D3E7"},{"vulnerable":true,"criteria":"cpe:2.3:a:f5:nginx_plus:r36:p2:*:*:*:*:*:*","matchCriteriaId":"862EA47E-8D57-434E-9C8F-238325FB85B2"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"27651","Ordinal":"1","Title":"NGINX ngx_mail_auth_http_module vulnerability","CVE":"CVE-2026-27651","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"27651","Ordinal":"1","NoteData":"When the ngx_mail_auth_http_module module is enabled on NGINX Plus or NGINX Open Source, undisclosed requests can cause worker processes to terminate. This issue may occur when (1) CRAM-MD5 or APOP authentication is enabled, and (2) the authentication server permits retry by returning the Auth-Wait response header. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.","Type":"Description","Title":"NGINX ngx_mail_auth_http_module vulnerability"}]}}}