ArduinoCore-avr has Stack-Based Buffer Overflow in WString Float/Double Constructors_CVE-2025-69209

{
    "lastseen": "",
    "description": "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/)",
    "published": "2026-01-21T20:00:41.026Z",
    "modified": "2026-01-21T21:28:52.505Z",
    "type": "cve",
    "title": "ArduinoCore-avr has Stack-Based Buffer Overflow in WString Float/Double Constructors",
    "source": "GitHub_M",
    "references": "https://github.com/arduino/ArduinoCore-avr/security/advisories/GHSA-pvx3-fm7w-6hjm\nhttps://github.com/arduino/ArduinoCore-avr/pull/613\nhttps://github.com/arduino/ArduinoCore-avr/commit/82a8ad2fb33911d8927c7af22e0472b94325d1a7\nhttps://github.com/arduino/ArduinoCore-avr/releases/tag/1.8.7\nhttps://support.arduino.cc/hc/en-us/articles/24985906702748-ASEC-26-001-ArduinoCore-AVR-v1-8-7-Resolves-Stack-Based-Buffer-Overflow-Vulnerability",
    "id": "CVE-2025-69209",
    "bulletinFamily": "",
    "cwe": [
        "CWE-120"
    ],
    "cvelist": null,
    "sourceData": "arduino ArduinoCore-avr < 1.8.7",
    "sourceHref": "",
    "cvss": {
        "score": 6.9,
        "severity": "MEDIUM",
        "vector": "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",
        "version": "4.0"
    },
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        "baseScore": 0,
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        "confidentialityImpact": "",
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        "availabilityImpact": "",
        "cvssV3": {
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "ArduinoCore-avr",
    "version": "< 1.8.7",
    "vendor": "arduino",
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    "ai_score": 0
}