CVE-2025-69209
What it is
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/)
At a glance
- Exploitability
- Can be exploited locally on the machine without logging in. High risk of service disruption.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.2% in the next 30 days (EPSS).
- Severity: 6.9 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Weakness
- CWE-120 · Classic buffer overflow
- Record status
- Deferred
Attack profile CVSS 4.0 · 6.9
- Attack vector
- Local
- Complexity
- Low
- Attack requirements
- None
- Privileges needed
- None
- User interaction
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2025-69209.md and follow it. Check whether this project is affected by CVE-2025-69209. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/arduino/ArduinoCore-avr/commit/82a8ad2fb33911d8927c7af22e0472b94325d1a7
- https://github.com/arduino/ArduinoCore-avr/pull/613
- https://github.com/arduino/ArduinoCore-avr/releases/tag/1.8.7
- https://github.com/arduino/ArduinoCore-avr/security/advisories/GHSA-pvx3-fm7w-6hjm
References
- https://github.com/arduino/ArduinoCore-avr/commit/82a8ad2fb33911d8927c7af22e0472b94325d1a7
- https://github.com/arduino/ArduinoCore-avr/pull/613
- https://github.com/arduino/ArduinoCore-avr/releases/tag/1.8.7
- https://github.com/arduino/ArduinoCore-avr/security/advisories/GHSA-pvx3-fm7w-6hjm
- https://support.arduino.cc/hc/en-us/articles/24985906702748-ASEC-26-001-ArduinoCore-AVR-v1-8-7-Resolves-Stack-Based-Buffer-Overflow-Vulnerability