Vulnerability-Lookup

Vulnerability from bitnami_vulndb

Published

2026-07-15 08:51

Modified

2026-07-15 09:15

Summary

ModSecurity: Multipart form-data parser silently strips embedded line breaks from form-field values, enabling request-body inspection bypass

Details

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Prior to 3.0.16, the multipart/form-data request body parser in libmodsecurity silently removes embedded line breaks from non-file form-field values before exporting them to ARGS and ARGS_POST because src/request_body_processor/multipart.cc overwrites reserved bytes in m_reserve instead of appending the current buffer. This creates a parser differential between ModSecurity and backend applications that preserve line breaks in form fields, allowing rules that inspect ARGS or ARGS_POST to miss payloads whose dangerous syntax depends on a line break. This issue is fixed in version 3.0.16.

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "modsecurity2",
        "purl": "pkg:bitnami/modsecurity2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.0.16"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-52747"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:trustwave:modsecurity:*:*:*:*:*:*:*:*"
    ],
    "severity": "High"
  },
  "details": "ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Prior to 3.0.16, the multipart/form-data request body parser in libmodsecurity silently removes embedded line breaks from non-file form-field values before exporting them to ARGS and ARGS_POST because src/request_body_processor/multipart.cc overwrites reserved bytes in m_reserve instead of appending the current buffer. This creates a parser differential between ModSecurity and backend applications that preserve line breaks in form fields, allowing rules that inspect ARGS or ARGS_POST to miss payloads whose dangerous syntax depends on a line break. This issue is fixed in version 3.0.16.",
  "id": "BIT-modsecurity2-2026-52747",
  "modified": "2026-07-15T09:15:52.837Z",
  "published": "2026-07-15T08:51:47.912Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/owasp-modsecurity/ModSecurity/commit/875504c2758169c41be1ad2f0cc64d896b7815d7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.16"
    },
    {
      "type": "WEB",
      "url": "https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-rcw9-2f5r-7p88"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52747"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "ModSecurity: Multipart form-data parser silently strips embedded line breaks from form-field values, enabling request-body inspection bypass"
}

CVE-2026-52747 (GCVE-0-2026-52747)

Vulnerability from cvelistv5 – Published: 2026-07-10 21:42 – Updated: 2026-07-13 17:48

Title

ModSecurity: Multipart form-data parser silently strips embedded line breaks from form-field values, enabling request-body inspection bypass

Summary

Severity

8.6 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-13 17:48 UTC

CWE

CWE-180 - Incorrect Behavior Order: Validate Before Canonicalize

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/owasp-modsecurity/ModSecurity/…	x_refsource_CONFIRM
https://github.com/owasp-modsecurity/ModSecurity/…	x_refsource_MISC
https://github.com/owasp-modsecurity/ModSecurity/…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
owasp-modsecurity	ModSecurity	Affected: < 3.0.16

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-52747",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-13T17:48:09.249154Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-13T17:48:27.282Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-rcw9-2f5r-7p88"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "ModSecurity",
          "vendor": "owasp-modsecurity",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 3.0.16"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Prior to 3.0.16, the multipart/form-data request body parser in libmodsecurity silently removes embedded line breaks from non-file form-field values before exporting them to ARGS and ARGS_POST because src/request_body_processor/multipart.cc overwrites reserved bytes in m_reserve instead of appending the current buffer. This creates a parser differential between ModSecurity and backend applications that preserve line breaks in form fields, allowing rules that inspect ARGS or ARGS_POST to miss payloads whose dangerous syntax depends on a line break. This issue is fixed in version 3.0.16."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 8.6,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-180",
              "description": "CWE-180: Incorrect Behavior Order: Validate Before Canonicalize",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-10T21:42:11.503Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-rcw9-2f5r-7p88",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-rcw9-2f5r-7p88"
        },
        {
          "name": "https://github.com/owasp-modsecurity/ModSecurity/commit/875504c2758169c41be1ad2f0cc64d896b7815d7",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/owasp-modsecurity/ModSecurity/commit/875504c2758169c41be1ad2f0cc64d896b7815d7"
        },
        {
          "name": "https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.16",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.16"
        }
      ],
      "source": {
        "advisory": "GHSA-rcw9-2f5r-7p88",
        "discovery": "UNKNOWN"
      },
      "title": "ModSecurity: Multipart form-data parser silently strips embedded line breaks from form-field values, enabling request-body inspection bypass"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-52747",
    "datePublished": "2026-07-10T21:42:11.503Z",
    "dateReserved": "2026-06-08T14:00:43.573Z",
    "dateUpdated": "2026-07-13T17:48:27.282Z",
    "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.