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

Vulnerability from cvelistv5 – Published: 2026-07-10 21:42 – Updated: 2026-07-10 21:42
VLAI
Title
ModSecurity: Multipart form-data parser silently strips embedded line breaks from form-field values, enabling request-body inspection bypass
Summary
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.
CWE
  • CWE-180 - Incorrect Behavior Order: Validate Before Canonicalize
Assigner
Impacted products
Show details on NVD website

{
  "containers": {
    "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": "2026-07-10T21:42:11.503Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-52747\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-07-10T22:16:42.697\",\"lastModified\":\"2026-07-10T22:16:42.697\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"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.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"owasp-modsecurity\",\"product\":\"ModSecurity\",\"versions\":[{\"version\":\"\u003c 3.0.16\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N\",\"baseScore\":8.6,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":3.9,\"impactScore\":4.0}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-180\"}]}],\"references\":[{\"url\":\"https://github.com/owasp-modsecurity/ModSecurity/commit/875504c2758169c41be1ad2f0cc64d896b7815d7\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.16\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-rcw9-2f5r-7p88\",\"source\":\"security-advisories@github.com\"}]}}"
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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