CVE-2025-69209

arduino-core-avr: ArduinoCore-avr contains the source code and configuration files of the Arduino AVR Boards platform

CVE-2025-69209 is fixed in arduino-core-avr on 1 platform, first by DEBIAN-CVE-2025-69209, released January 21, 2026. It is not reported as exploited. Patch Radar priority: Routine.

Routine
CVSS
n/a
No vendor severity
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0018
7th percentile

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. ### Patches - 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) - The Fixing Commit is available at the following link [1a6a417f89c8901dad646efce74ae9d3ddebfd59](https://github.com/arduino/ArduinoCore-avr/pull/613/commits/1a6a417f89c8901dad646efce74ae9d3ddebfd59) ### References - [ASEC-26-001 ArduinoCore-avr vXXXX Resolves Buffer Overflow Vulnerability](https://support.arduino.cc/hc/en-us/articles/XXXXX) ### Credits - Maxime Rossi Bellom and Ramtine Tofighi Shirazi from SecMate (https://secmate.dev/)

Where it's fixed

ProductFixed inFixReleased
Linux
arduino-core-avr · Debian 12.15 (bookworm) 1.8.7+dfsg-1~deb12u1 DEBIAN-CVE-2025-69209 Jan 21, 2026
arduino-core-avr · Debian 13.5 (trixie) 1.8.7+dfsg-1~deb13u1 DEBIAN-CVE-2025-69209 Jan 21, 2026
arduino-core-avr · Debian 14 1.8.7+dfsg-1 DEBIAN-CVE-2025-69209 Jan 21, 2026

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