CVE-2026-48490: Buffer Overflow

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.

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Weakness Type (CWE)

CWE-120 CWE-120

References

Other References

https://github.com/arduino/ArduinoCore-avr/pull/622/changes/9492e146880d2b05d9cb9191f1bfb2c872a48404 https://github.com/arduino/ArduinoCore-avr/releases/tag/1.8.8 https://github.com/arduino/ArduinoCore-avr/security/advisories/GHSA-fhp2-f8hw-mgpj

Frequently Asked Questions

What is CVE-2026-48490? +

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.

How do I check if I'm vulnerable to CVE-2026-48490? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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