{"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"}}]}}

{"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": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-28753", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-03-24T15:24:28.689685Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-03-24T15:24:31.847Z"}}]}}

{"cveTags": [], "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."}], "id": "CVE-2026-28753", "lastModified": "2026-03-24T15:53:48.067", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 3.7, "baseSeverity": "LOW", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 1.4, "source": "f5sirt@f5.com", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.3, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "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/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", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "f5sirt@f5.com", "type": "Secondary"}]}, "published": "2026-03-24T15:16:33.560", "references": [{"source": "f5sirt@f5.com", "url": "https://my.f5.com/manage/s/article/K000160367"}], "sourceIdentifier": "f5sirt@f5.com", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-93"}], "source": "f5sirt@f5.com", "type": "Primary"}]}

{"bugzilla": {"description": "NGINX: NGINX Plus: NGINX Open Source: NGINX Plus and NGINX Open Source: Request manipulation via header injection in SMTP upstream requests", "id": "2450780", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2450780"}, "csaw": false, "cvss3": {"cvss3_base_score": "3.7", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N", "status": "draft"}, "cwe": "CWE-93", "details": ["A flaw was found in NGINX Plus and NGINX Open Source, specifically within the ngx_mail_smtp_module. This vulnerability allows an attacker-controlled DNS (Domain Name System) server to inject arbitrary headers into SMTP (Simple Mail Transfer Protocol) upstream requests. This is due to the improper handling of Carriage Return (CRLF) sequences in DNS responses. The primary consequence is the potential manipulation of these requests, which could alter their intended behavior."], "mitigation": {"lang": "en:us", "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability."}, "name": "CVE-2026-28753", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "nginx", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "nginx:1.24/nginx", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "nginx", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "nginx:1.24/nginx", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "nginx:1.26/nginx", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-03-24T14:13:26Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-28753\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-28753\nhttps://my.f5.com/manage/s/article/K000160367"], "threat_severity": "Low"}

{}