FKIE_CVE-2026-56434

Vulnerability from fkie_nvd - Published: 2026-07-15 15:16 - Updated: 2026-07-15 16:23
Severity
6.5 (Medium) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
Summary
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_ssi_module module. This vulnerability may exist when the Server-Side Includes (SSI), proxy_pass, and proxy_buffering off directives are configured. With this configuration, an unauthenticated attacker with man-in-the-middle (MITM) ability to control responses from an upstream server may be able to cause a heap buffer over-read in the NGINX worker process. This issue may lead to limited modification of memory or a restart of the NGINX worker process. Impact: This vulnerability may allow remote attackers to have limited control to modify memory contents or restart the NGINX worker process. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
References
f5sirt@f5.comhttps://my.f5.com/manage/s/article/K000162098
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unknown",
          "modules": [
            "ngx_http_ssi_module"
          ],
          "product": "NGINX Plus",
          "vendor": "F5",
          "versions": [
            {
              "lessThan": "37.0.3.1",
              "status": "affected",
              "version": "37.0.0.1",
              "versionType": "custom"
            },
            {
              "lessThan": "R36 P7",
              "status": "affected",
              "version": "R36",
              "versionType": "custom"
            },
            {
              "lessThan": "*",
              "status": "affected",
              "version": "R33",
              "versionType": "custom"
            }
          ]
        },
        {
          "defaultStatus": "unknown",
          "modules": [
            "ngx_http_ssi_module"
          ],
          "product": "NGINX Open Source",
          "vendor": "F5",
          "versions": [
            {
              "lessThan": "1.31.3",
              "status": "affected",
              "version": "1.31.2",
              "versionType": "custom"
            },
            {
              "lessThan": "1.30.4",
              "status": "affected",
              "version": "0.8.11",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "f5sirt@f5.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_ssi_module\u00a0module. This vulnerability may exist when the Server-Side Includes (SSI), proxy_pass, and proxy_buffering off\u00a0directives are configured. With this configuration, an unauthenticated attacker with man-in-the-middle (MITM) ability to control responses from an upstream server may be able to cause a heap buffer over-read in the NGINX worker process. This issue may lead to limited modification of memory or a restart of the NGINX worker process.\n\nImpact:\nThis vulnerability may allow remote attackers to have limited control to modify memory contents or restart the NGINX worker process. There is no control plane exposure; this is a data plane issue only.\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated."
    }
  ],
  "id": "CVE-2026-56434",
  "lastModified": "2026-07-15T16:23:03.437",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "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:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 4.2,
        "source": "f5sirt@f5.com",
        "type": "Secondary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 8.3,
          "baseSeverity": "HIGH",
          "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:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/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": "HIGH",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "LOW",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "f5sirt@f5.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-56434",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-15T15:38:13.231118Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-15T15:16:45.700",
  "references": [
    {
      "source": "f5sirt@f5.com",
      "url": "https://my.f5.com/manage/s/article/K000162098"
    }
  ],
  "sourceIdentifier": "f5sirt@f5.com",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ],
      "source": "f5sirt@f5.com",
      "type": "Secondary"
    }
  ]
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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