What is the CVSS score of CVE-2026-38971?

CVE-2026-38971 has a CVSS 3.1 base score of 9.1 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H. EPSS exploitation probability: 0.2%.

Which versions of ArduPilot are affected by CVE-2026-38971?

ArduPilot flight autopilot systems (Plane through version 4.6.3) are vulnerable to unauthenticated remote attacks via the MAVLink ground control interface that can leak sensitive system memory or…

How to fix or mitigate CVE-2026-38971?

Within 24 hours: inventory all ArduPilot Plane deployments (version 4.6.3 and earlier) and assess exposure to untrusted MAVLink connections; immediately block external MAVLink traffic if operationally feasible. Within 7 days: implement firewall rules or network segmentation to restrict MAVLink access to trusted ground-control systems only; disable SERIAL_CONTROL message processing if operationally feasible. Within 30 days: contact ArduPilot vendor for official patch timeline; test patch in non-production environment; deploy to all vulnerable systems immediately upon vendor release.

ArduPilot CVE-2026-38971

CRITICAL

Out-of-bounds Read (CWE-125)

2026-07-02 mitre

Buffer Overflow Information Disclosure N A

9.1

CVSS 3.1 · Vendor: mitre

Severity by source

Vendor (mitre) PRIMARY

9.1 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

vuln.today AI

9.1 CRITICAL

Unauthenticated crafted MAVLink message (AV:N/AC:L/PR:N/UI:N); OOB read leaks memory back over serial passthrough (C:H) and can crash the autopilot (A:H), no integrity impact.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (mitre).

CVSS VectorVendor: mitre

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

High

Lifecycle Timeline

Analysis Generated

Jul 06, 2026 - 18:30 vuln.today

CVSS changed

Jul 06, 2026 - 18:22 NVD

9.1 (CRITICAL)

CVE Published

Jul 02, 2026 - 00:00 cve.org

UNKNOWN (no severity yet)

DescriptionCVE.org

ardupilot through Plane-4.6.3 was found to contain an out-of-bounds read issue in libraries/GCS_MAVLink/GCS_serial_control.cpp in GCS_MAVLINK::handle_serial_control().

AnalysisAI

Out-of-bounds read in ArduPilot's MAVLink ground-control-station handler (through Plane-4.6.3) lets a remote attacker on the MAVLink link send a crafted SERIAL_CONTROL message that reads memory beyond intended bounds in GCS_MAVLINK::handle_serial_control(), potentially disclosing adjacent flight-controller memory and/or crashing the autopilot. The CVSS 9.1 rating reflects high confidentiality and availability impact over an unauthenticated network vector, though EPSS is low (0.17%, 6th percentile) and no public exploit is identified at time of analysis. An upstream fix is proposed via GitHub PR #32587 (issue #32524), but no tagged patched release is independently confirmed.

Technical ContextAI

ArduPilot is a widely-used open-source autopilot firmware for UAVs, rovers, and boats; the affected code is libraries/GCS_MAVLink/GCS_serial_control.cpp, which implements handling of the MAVLink SERIAL_CONTROL message used to bridge a ground control station (GCS) to a physical/virtual serial port on the vehicle (e.g., for passthrough to peripherals or bootloaders). The root cause is CWE-125 (Out-of-bounds Read): handle_serial_control() apparently trusts a length/count field or buffer index from the incoming SERIAL_CONTROL payload without validating it against the actual buffer size, causing reads past the buffer boundary. Because SERIAL_CONTROL supports reading data back to the GCS, an over-read can both leak process memory into the returned MAVLink stream and destabilize the flight controller. The CPE data supplied ('cpe:2.3:a:n/a:n/a:*') is a placeholder and provides no usable version enumeration.

RemediationAI

Upstream fix available (PR/commit); released patched version not independently confirmed - track and apply ArduPilot pull request #32587 (issue #32524) and upgrade to the first tagged release that includes it once published, rather than relying on the pre-4.6.3 line. As compensating controls until a patched firmware build is deployed: do not expose MAVLink telemetry endpoints (UDP/TCP) directly to untrusted networks - bind them to localhost or a trusted management VLAN and place them behind a firewall so only authorized GCS hosts can reach the port (side effect: remote/cloud GCS tooling must be routed through a VPN or bastion); where feasible enable MAVLink 2 signing/authentication so unsigned SERIAL_CONTROL messages from unauthorized senders are rejected (side effect: all legitimate GCS and companion-computer clients must be configured with the shared key); and restrict or disable SERIAL_CONTROL passthrough functionality if it is not operationally required (side effect: loses GCS-driven serial passthrough/peripheral bootloading). See the ArduPilot GitHub issue/PR for authoritative fix details.