{"id":"CVE-2025-69209","summary":"ArduinoCore-avr has Stack-Based Buffer Overflow in WString Float/Double Constructors","details":"ArduinoCore-avr contains the source code and configuration files of the Arduino AVR Boards platform. A vulnerability in versions prior to 1.8.7 allows an attacker to trigger a stack-based buffer overflow when converting floating-point values to strings with high precision. By passing very large `decimalPlaces` values to the affected String constructors or concat methods, the `dtostrf` function writes beyond fixed-size stack buffers, causing memory corruption and denial of service. Under specific conditions, this could enable arbitrary code execution on AVR-based Arduino boards.\n\n### Patches\n\n- The Fix is included starting from the `1.8.7` release available from the following link [ArduinoCore-avr v1.8.7](https://github.com/arduino/ArduinoCore-avr)\n\n- The Fixing Commit is available at the following link [1a6a417f89c8901dad646efce74ae9d3ddebfd59](https://github.com/arduino/ArduinoCore-avr/pull/613/commits/1a6a417f89c8901dad646efce74ae9d3ddebfd59)\n\n### References\n\n- [ASEC-26-001 ArduinoCore-avr vXXXX Resolves Buffer Overflow Vulnerability](https://support.arduino.cc/hc/en-us/articles/XXXXX)\n\n### Credits\n\n- Maxime Rossi Bellom and Ramtine Tofighi Shirazi from SecMate (https://secmate.dev/)","aliases":["GHSA-pvx3-fm7w-6hjm"],"modified":"2026-08-12T03:51:11.564728861Z","published":"2026-01-21T20:00:41.026Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/69xxx/CVE-2025-69209.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-120"]},"references":[{"type":"WEB","url":"https://github.com/arduino/ArduinoCore-avr/releases/tag/1.8.7"},{"type":"WEB","url":"https://support.arduino.cc/hc/en-us/articles/24985906702748-ASEC-26-001-ArduinoCore-AVR-v1-8-7-Resolves-Stack-Based-Buffer-Overflow-Vulnerability"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/69xxx/CVE-2025-69209.json"},{"type":"ADVISORY","url":"https://github.com/arduino/ArduinoCore-avr/security/advisories/GHSA-pvx3-fm7w-6hjm"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-69209"},{"type":"FIX","url":"https://github.com/arduino/ArduinoCore-avr/commit/82a8ad2fb33911d8927c7af22e0472b94325d1a7"},{"type":"FIX","url":"https://github.com/arduino/ArduinoCore-avr/pull/613"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/arduino/arduinocore-avr","events":[{"introduced":"0"},{"fixed":"82a8ad2fb33911d8927c7af22e0472b94325d1a7"},{"fixed":"d5d1355b95fd57bbcd30b86db5dc0003440eee8d"}],"database_specific":{"source":["AFFECTED_FIELD","REFERENCES"],"extracted_events":[{"introduced":"0"},{"fixed":"1.8.7"}]}}],"versions":["1.8.6","1.8.5","1.8.4","1.8.3","1.8.2","1.8.1","1.6.23","1.6.22"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-69209.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}]}