CVE-2026-87121NVD

Vulnerability Summary

lwIP TCP/IP Stack MQTT is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device.

Severity Level

CRITICAL(9.8)

Published Date

Sep 22, 2026

Last Modified

Sep 22, 2026

Exploitation Status

No confirmed exploitation yet

EPSS Score (30-Day)

Data Pending

Root Weakness (CWE)

CWE-787: Unknown/Unlisted Weakness ↗

Refer to the official MITRE database for detailed architectural specifications regarding this weakness.

CVSS v4.0 Base Metrics — Score 9.3 (CRITICAL)

Attack VectorNetwork

Attack ComplexityLow

Attack RequirementsNone

Privileges RequiredNone

User InteractionNone

Confidentiality (Vulnerable System)High

Integrity (Vulnerable System)High

Availability (Vulnerable System)High

Confidentiality (Subsequent System)None

Integrity (Subsequent System)None

Availability (Subsequent System)None

CVSS v3.1 Base Metrics — Score 9.8 (CRITICAL)

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

Affected & Patched Versions

Affected Versions

lwIP TCP/IP Stack MQTT >= 2.0.1 and <= 2.2.1

Patched Versions

lwIP TCP/IP Stack MQTT 2.2.1

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