{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-27651","assignerOrgId":"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab","state":"PUBLISHED","assignerShortName":"f5","dateReserved":"2026-03-18T16:06:38.454Z","datePublished":"2026-03-24T14:13:27.295Z","dateUpdated":"2026-03-24T15:14:13.220Z"},"containers":{"cna":{"providerMetadata":{"orgId":"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab","shortName":"f5","dateUpdated":"2026-03-24T14:22:35.756Z"},"title":"NGINX ngx_mail_auth_http_module vulnerability","datePublic":"2026-03-24T14:00:00.000Z","problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-476","description":"CWE-476 NULL Pointer Dereference","type":"CWE"}]}],"affected":[{"vendor":"F5","product":"NGINX Open Source","modules":["ngx_mail_auth_http_module"],"versions":[{"status":"affected","version":"1.29.0","lessThan":"1.29.7","versionType":"semver"},{"status":"affected","version":"0.5.15","lessThan":"1.28.3","versionType":"semver"}],"defaultStatus":"unknown"},{"vendor":"F5","product":"NGINX Plus","modules":["ngx_mail_auth_http_module"],"versions":[{"status":"affected","version":"R36","lessThan":"R36 P3","versionType":"custom"},{"status":"affected","version":"R35","lessThan":"R35 P2","versionType":"custom"},{"status":"affected","version":"R34","lessThan":"*","versionType":"custom"},{"status":"affected","version":"R33","lessThan":"*","versionType":"custom"},{"status":"affected","version":"R32","lessThan":"R32 P5","versionType":"custom"}],"defaultStatus":"unaffected"}],"descriptions":[{"lang":"en","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.","supportingMedia":[{"type":"text/html","base64":false,"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."}]}],"references":[{"url":"https://my.f5.com/manage/s/article/K000160383","tags":["vendor-advisory"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH","baseSeverity":"HIGH","baseScore":7.5,"vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"version":"4.0","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","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":8.7,"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"}}],"credits":[{"lang":"en","value":"F5 acknowledges Arkadi Vainbrand 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":"2026-03-24T15:02:03.137056Z","id":"CVE-2026-27651","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-03-24T15:14:13.220Z"}}]}}