CVE-2026-48490 ArduinoCore-AVR: Stack-Based Buffer Overflow in String float/double concatenation handler
Attacker can trigger stack buffer overflow via large float concatenation, causing DoS or code execution on Arduino AVR boards.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-48490?
CVE-2026-48490 is a medium-severity memory corruption vulnerability in ArduinoCore-avr, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-120
Which versions are affected by CVE-2026-48490?
How do I fix CVE-2026-48490?
No fix has been published for CVE-2026-48490 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-48490 being exploited?
There is no known exploitation of CVE-2026-48490 in the wild and no public exploit code.
Sources
Also known as GHSA-fhp2-f8hw-mgpj.