EUVD-2026-76769Severity by source
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/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
AV:N for network-connected sketches; AC:L as crafting a near-FLT_MAX value is trivial; A:H for stack corruption causing device crash; I:L for conditional but unconfirmed RCE.
Primary rating from Vendor (github).
CVSS VectorVendor: github
Lifecycle Timeline
3DescriptionCVE.org
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.
AnalysisAI
Stack-based buffer overflow in ArduinoCore-avr versions prior to 1.8.8 allows an attacker who can influence float or double values passed to Arduino String concatenation methods to corrupt stack memory on AVR-based Arduino boards, causing denial of service and - under specific conditions - arbitrary code execution on the microcontroller. The flaw resides in String::concat(float) and String::concat(double) in WString.cpp, where a fixed 20-byte stack buffer is insufficient for values near the extremes of the float or double range when processed by dtostrf(). …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires all three of the following conditions simultaneously: (1) the target Arduino AVR board has an active communication channel that accepts externally controlled data (e.g., network interface via Ethernet or WiFi shield, Bluetooth, serial-over-USB, or similar); (2) the sketch converts that external data to a C float or double type; and (3) the resulting float/double is passed to String::concat(float), String::concat(double), String::operator+=(float/double), or the + operator with a float/double operand in ArduinoCore-avr prior to 1.8.8. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 base vector (AV:N/AC:L/AT:N/PR:N/UI:N, score 6.9) reflects the scenario where a network-connected Arduino sketch can receive attacker-controlled data and pass it through the vulnerable path without authentication or user interaction. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Vendor-released patch: ArduinoCore-avr 1.8.8. … Detailed patch versions, workarounds, and compensating controls in full report. |
Threat intelligence, references, and detailed analysis are available after sign-in.
Same weakness CWE-120 – Classic Buffer Overflow
View allShare
External POC / Exploit Code
Leaving vuln.today