{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-28753","assignerOrgId":"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab","state":"PUBLISHED","assignerShortName":"f5","dateReserved":"2026-03-18T16:06:38.435Z","datePublished":"2026-03-24T14:13:26.107Z","dateUpdated":"2026-03-24T15:24:34.995Z"},"containers":{"cna":{"providerMetadata":{"orgId":"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab","shortName":"f5","dateUpdated":"2026-03-24T14:49:49.169Z"},"title":"NGINX ngx_mail_proxy_module vulnerability","datePublic":"2026-03-24T14:00:00.000Z","problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-93","description":"CWE-93 Improper Neutralization of CRLF Sequences ('CRLF Injection')","type":"CWE"}]}],"affected":[{"vendor":"F5","product":"NGINX Open Source","modules":["ngx_mail_proxy_module"],"versions":[{"status":"affected","version":"1.29.0","lessThan":"1.29.7","versionType":"semver"},{"status":"affected","version":"0.6.27","lessThan":"1.28.3","versionType":"semver"}],"defaultStatus":"unknown"},{"vendor":"F5","product":"NGINX Plus","modules":["ngx_mail_proxy_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":"unknown"}],"descriptions":[{"lang":"en","value":"NGINX Plus and NGINX Open Source have a vulnerability in the ngx_mail_smtp_module module due to the improper handling of CRLF sequences in DNS responses. This allows an attacker-controlled DNS server to inject arbitrary headers into SMTP upstream requests, leading to potential request manipulation. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.","supportingMedia":[{"type":"text/html","base64":false,"value":"NGINX Plus and NGINX Open Source have a vulnerability in the ngx_mail_smtp_module module due to the improper handling of CRLF sequences in DNS responses. This allows an attacker-controlled DNS server to inject arbitrary headers into SMTP upstream requests, leading to potential request manipulation. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated."}]}],"references":[{"url":"https://my.f5.com/manage/s/article/K000160367","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":"NONE","integrityImpact":"LOW","availabilityImpact":"NONE","baseSeverity":"LOW","baseScore":3.7,"vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"version":"4.0","attackVector":"NETWORK","attackComplexity":"HIGH","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subAvailabilityImpact":"NONE","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","baseSeverity":"MEDIUM","baseScore":6.3,"vectorString":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"}}],"credits":[{"lang":"en","value":"Asim Viladi Oglu Manizada","type":"reporter"},{"lang":"en","value":"Colin Warren","type":"reporter"},{"lang":"en","value":"Xiao Liu (Yunnan University)","type":"reporter"},{"lang":"en","value":"Yuan Tan (UC Riverside)","type":"reporter"},{"lang":"en","value":"Bird Liu (Lanzhou University)","type":"reporter"}],"source":{"discovery":"EXTERNAL"},"x_generator":{"engine":"F5 SIRTBot v1.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-24T15:24:28.689685Z","id":"CVE-2026-28753","options":[{"Exploitation":"none"},{"Automatable":"no"},{"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":"2026-03-24T15:24:34.995Z"}}]}}