FKIE_CVE-2026-42854

Vulnerability from fkie_nvd - Published: 2026-05-12 22:16 - Updated: 2026-06-17 10:48
Severity
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
arduino-esp32 is an Arduino core for the ESP32, ESP32-S2, ESP32-S3, ESP32-C3, ESP32-C6 and ESP32-H2 microcontrollers. Prior to 3.3.8, the WebServer multipart form parser in arduino-esp32 allocates a Variable Length Array (VLA) on the stack whose size is derived from an attacker-controlled HTTP header field (Content-Type: multipart/form-data; boundary=...) without enforcing any length limit. Sending a boundary string longer than ~8000 characters overflows the 8192-byte task stack of the loopTask, causing a crash and potential remote code execution. This vulnerability is fixed in 3.3.8.
References
security-advisories@github.comhttps://github.com/espressif/arduino-esp32/security/advisories/GHSA-8cmm-3887-r32jExploit, Vendor Advisory
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/espressif/arduino-esp32/security/advisories/GHSA-8cmm-3887-r32jExploit, Vendor Advisory
Impacted products
Vendor Product Version
espressif arduino-esp32 *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "arduino-esp32",
          "vendor": "espressif",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 3.3.8"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
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      "nodes": [
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          "cpeMatch": [
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              "criteria": "cpe:2.3:a:espressif:arduino-esp32:*:-:*:*:*:*:*:*",
              "matchCriteriaId": "308785AC-A885-47B5-9131-64AE662B6525",
              "versionEndExcluding": "3.3.8",
              "vulnerable": true
            }
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          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "arduino-esp32 is an Arduino core for the ESP32, ESP32-S2, ESP32-S3, ESP32-C3, ESP32-C6 and ESP32-H2 microcontrollers. Prior to 3.3.8, the WebServer multipart form parser in arduino-esp32 allocates a Variable Length Array (VLA) on the stack whose size is derived from an attacker-controlled HTTP header field (Content-Type: multipart/form-data; boundary=...) without enforcing any length limit. Sending a boundary string longer than ~8000 characters overflows the 8192-byte task stack of the loopTask, causing a crash and potential remote code execution. This vulnerability is fixed in 3.3.8."
    }
  ],
  "id": "CVE-2026-42854",
  "lastModified": "2026-06-17T10:48:30.760",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
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        "impactScore": 5.9,
        "source": "security-advisories@github.com",
        "type": "Secondary"
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    ],
    "ssvcV203": [
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        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-42854",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-05-13T14:24:33.796662Z",
          "version": "2.0.3"
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  },
  "published": "2026-05-12T22:16:34.930",
  "references": [
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      "tags": [
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      "url": "https://github.com/espressif/arduino-esp32/security/advisories/GHSA-8cmm-3887-r32j"
    },
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  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
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      "description": [
        {
          "lang": "en",
          "value": "CWE-121"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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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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