Vulnerability-Lookup

Vulnerability from bitnami_vulndb

Published

2026-03-27 07:10

Modified

2026-09-08 08:34

Summary

NGINX ngx_mail_proxy_module vulnerability

Details

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.

JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "nginx",
        "purl": "pkg:bitnami/nginx"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.6.27"
            },
            {
              "fixed": "1.28.3"
            },
            {
              "introduced": "1.29.0"
            },
            {
              "fixed": "1.29.7"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "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",
          "type": "CVSS_V4"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-28753"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:f5:nginx:*:*:*:*:*:*:*:*"
    ],
    "severity": "Medium"
  },
  "details": "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": "BIT-nginx-2026-28753",
  "modified": "2026-09-08T08:34:36.952Z",
  "published": "2026-03-27T07:10:10.953Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://my.f5.com/manage/s/article/K000160367"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-28753"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "NGINX ngx_mail_proxy_module vulnerability"
}

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

Vulnerability from cvelistv5 – Published: 2026-03-24 14:13 – Updated: 2026-03-24 15:24

Title

NGINX ngx_mail_proxy_module vulnerability

Summary

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 mitre root

References

1 reference

URL	Tags
https://my.f5.com/manage/s/article/K000160367	vendor-advisory

Impacted products

2 products

Vendor	Product	Version
F5	NGINX Open Source	Affected: 1.29.0 , < 1.29.7 (semver) Affected: 0.6.27 , < 1.28.3 (semver)
F5	NGINX Plus	Affected: R36 , < R36 P3 (custom) Affected: R35 , < R35 P2 (custom) Affected: R34 , < * (custom) Affected: R33 , < * (custom) Affected: R32 , < R32 P5 (custom)

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

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-28753",
                "options": [
                  {
                    "Exploitation": "none"
                  },
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                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-24T15:24:28.689685Z",
                "version": "2.0.3"
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          "dateUpdated": "2026-03-24T15:24:34.995Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
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          "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"
            },
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              "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"
            },
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              "lessThan": "*",
              "status": "affected",
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            },
            {
              "lessThan": "*",
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              "version": "R33",
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            },
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        },
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          "lang": "en",
          "type": "reporter",
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        }
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        }
      ],
      "metrics": [
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            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 3.7,
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            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
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            "version": "3.1"
          },
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          "scenarios": [
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              "lang": "en",
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        },
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            "valueDensity": "NOT_DEFINED",
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            "vulnerabilityResponseEffort": "NOT_DEFINED"
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              "type": "CWE"
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          ]
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      ],
      "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"
      }
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  "cveMetadata": {
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    "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"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.