{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-42854", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-04-30T16:44:48.378Z", "datePublished": "2026-05-12T21:56:33.437Z", "dateUpdated": "2026-05-12T21:56:33.437Z"}, "containers": {"cna": {"title": "arduino-esp32: Stack buffer overflow in WebServer multipart boundary parsing leads to remote crash potential RCE", "problemTypes": [{"descriptions": [{"cweId": "CWE-121", "lang": "en", "description": "CWE-121: Stack-based Buffer Overflow", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"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"}}], "references": [{"name": "https://github.com/espressif/arduino-esp32/security/advisories/GHSA-8cmm-3887-r32j", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/espressif/arduino-esp32/security/advisories/GHSA-8cmm-3887-r32j"}], "affected": [{"vendor": "espressif", "product": "arduino-esp32", "versions": [{"version": "< 3.3.8", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-05-12T21:56:33.437Z"}, "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."}], "source": {"advisory": "GHSA-8cmm-3887-r32j", "discovery": "UNKNOWN"}}}}

{}

{"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": "2026-05-12T22:16:34.930", "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"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-05-12T22:16:34.930", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/espressif/arduino-esp32/security/advisories/GHSA-8cmm-3887-r32j"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-121"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,3.3.8)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "arduino-esp32", "source": "cna", "vendor": "espressif"}, "product": "arduino-esp32", "vendor": "espressif"}], "created": "2026-05-12T23:45:25.190641+00:00", "updated": "2026-05-12T23:45:25.452727+00:00", "vendors": ["espressif", "espressif$PRODUCT$arduino-esp32"]}