Vulnerability · Published Sep 11, 2026 · Assigned by GitHub_M
CVE-2026-48490ArduinoCore-AVR: Stack-Based Buffer Overflow in String float/double concatenation handler
Medium 6.9
In plain English
A medium-severity buffer overflow in ArduinoCore-avr from arduino. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 52% of all known vulnerabilities).
Official description
ArduinoCore-avr contains the source code and configuration files of the Arduino AVR Boards platform. A vulnerability in versions prior to 1.8.8 allows an attacker to trigger a stack-based buffer overflow when concatenating floating-point values of sufficiently large magnitude onto an Arduino String object. By passing values near the extremes of the float or double range to `String::concat(float)`, `String::concat(double)`, `String::operator+=()`, or the `+` operator with a float/double operand, `dtostrf()` writes beyond the fixed-size stack buffer, causing memory corruption and denial of service. Under specific conditions, this could enable arbitrary code execution on AVR-based Arduino boards. The fix is included starting from the `1.8.8 `release.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| arduino | ArduinoCore-avr | < 1.8.8 |
Weakness: CWE-120 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N