{"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":"2026-05-13T14:24:52.597Z"},"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"}},"adp":[{"references":[{"url":"https://github.com/espressif/arduino-esp32/security/advisories/GHSA-8cmm-3887-r32j","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-13T14:24:33.796662Z","id":"CVE-2026-42854","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-05-13T14:24:52.597Z"}}]}}