TS
Product
TCP/IP Stack MQTT
1
CVEs
0
On KEV
9.8
Max CVSS
0
New 30D
VulnerabilityCritical
lwIP TCP/IP Stack MQTT Client Application
View CSAF
Summary
Successful exploitation of this vulnerability could allow an attacker to gain full code execution on the device.
The following versions of lwIP TCP/IP Stack MQTT Client Application are affected:
MQTT Client Application >=2.0.1|<=2.2.1 (CVE-2026-87121)
CVSS
Vendor
Equipment
Vulnerabilities
v3 9.8
lwIP
lwIP TCP/IP Stack MQTT Client Application
Out-of-bounds Write
Background
Critical Infrastructure Sectors: Chemical, Communications, Critical Manufacturing, Energy, Financial Services, Healthcare and Public Health, Transportation Systems, Water and Wastewater Systems
Countries/Areas Deployed: Worldwide
Company Headquarters Location: Sweden
Vulnerabilities
Expand All +
CVE-2026-87121
The affected product is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device.
View CVE Details
Affected Products
lwIP TCP/IP Stack MQTT Client Application
Vendor: lwIP
Product Version: lwIP MQTT Client Application: >=2.0.1|<=2.2.1
Product Status: known_affected
Remediations
Mitigation Users of lwIP are encouraged to update their version of lwIP using the repository found at https://savannah.nongnu.org/projects/lwip . The commit identifier that contains the fix is f89407ea711879c04d91c92b35d67be78bbaf0f1.
Relevant CWE: CWE-787 Out-of-bounds Write
Metrics
CVSS Versi...
Sep 22, 2026·CISA Advisories
