CVE-2026-28753 (GCVE-0-2026-28753)

Vulnerability from cvelistv5 – Published: 2026-03-24 14:13 – Updated: 2026-03-24 15:24
VLAI
Title
NGINX ngx_mail_proxy_module vulnerability
Summary
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.
Severity
3.7 (Low)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
6.3 (Medium)
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
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-03-24 15:24 UTC
CWE
  • CWE-93 - Improper Neutralization of CRLF Sequences ('CRLF Injection')
Assigner
f5 CNA under the mitre root
CNA scorecard B 84/100 over 87 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
F5 NGINX Open Source Affected: 1.29.0 , < 1.29.7 (semver)
Affected: 0.6.27 , < 1.28.3 (semver)
guessed Create a notification for this product.
F5 NGINX Plus Affected: R36 , < R36 P3 (custom)
Affected: R35 , < R35 P2 (custom)
Affected: R34 , < * (custom)
Affected: R33 , < * (custom)
Affected: R32 , < R32 P5 (custom)
guessed Create a notification for this product.
Date Public
2026-03-24 14:00
Credits
Asim Viladi Oglu Manizada Colin Warren Xiao Liu (Yunnan University) Yuan Tan (UC Riverside) Bird Liu (Lanzhou University)
Show details on NVD website
To clipboard 

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              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-03-24T15:24:31.847Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unknown",
              "modules": [
                "ngx_mail_proxy_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": "0.6.27",
                  "versionType": "semver"
                }
              ]
            },
            {
              "defaultStatus": "unknown",
              "modules": [
                "ngx_mail_proxy_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": "Asim Viladi Oglu Manizada"
            },
            {
              "lang": "en",
              "type": "reporter",
              "value": "Colin Warren"
            },
            {
              "lang": "en",
              "type": "reporter",
              "value": "Xiao Liu (Yunnan University)"
            },
            {
              "lang": "en",
              "type": "reporter",
              "value": "Yuan Tan (UC Riverside)"
            },
            {
              "lang": "en",
              "type": "reporter",
              "value": "Bird Liu (Lanzhou University)"
            }
          ],
          "datePublic": "2026-03-24T14:00:00.000Z",
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "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."
                }
              ],
              "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."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "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"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            },
            {
              "cvssV4_0": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "HIGH",
                "attackRequirements": "PRESENT",
                "attackVector": "NETWORK",
                "baseScore": 6.3,
                "baseSeverity": "MEDIUM",
                "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",
                "version": "4.0",
                "vulnAvailabilityImpact": "NONE",
                "vulnConfidentialityImpact": "NONE",
                "vulnIntegrityImpact": "LOW",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-93",
                  "description": "CWE-93 Improper Neutralization of CRLF Sequences (\u0027CRLF Injection\u0027)",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-03-24T14:49:49.169Z",
            "orgId": "9dacffd4-cb11-413f-8451-fbbfd4ddc0ab",
            "shortName": "f5"
          },
          "references": [
            {
              "tags": [
                "vendor-advisory"
              ],
              "url": "https://my.f5.com/manage/s/article/K000160367"
            }
          ],
          "source": {
            "discovery": "EXTERNAL"
          },
          "title": "NGINX ngx_mail_proxy_module vulnerability",
          "x_generator": {
            "engine": "F5 SIRTBot v1.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "9dacffd4-cb11-413f-8451-fbbfd4ddc0ab",
        "assignerShortName": "f5",
        "cveId": "CVE-2026-28753",
        "datePublished": "2026-03-24T14:13:26.107Z",
        "dateReserved": "2026-03-18T16:06:38.435Z",
        "dateUpdated": "2026-03-24T15:24:34.995Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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