lwIP TCP/IP Stack MQTT Client Application

Summary

Vulnerabilities 1

• Critical 9.8
  CVE-2026-87121

  Out-of-bounds write in lwIP TCP/IP Stack MQTT Client Application

  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.

  lwIP TCP/IP Stack MQTT lwip lwip Debian Ubuntu
  Sep 22, 2026

Revision history

1. 2026-09-22 #1

   Initial Publication

References

• ICSA Advisory ICSA-26-265-01 - Web Version
  https://www.cisa.gov/news-events/ics-advisories/icsa-26-265-01
• Recommended Practices
  https://www.cisa.gov/uscert/ics/alerts/ICS-ALERT-10-301-01
• Recommended Practices
  https://www.cisa.gov/resources-tools/resources/ics-recommended-practices
• Recommended Practices
  https://www.cisa.gov/sites/default/files/publications/Cybersecurity_Best_Practices_for_Industrial_Control_Systems.pdf
• Recommended Practices
  https://www.cisa.gov/topics/industrial-control-systems
• Recommended Practices
  https://www.cisa.gov/uscert/sites/default/files/publications/emailscams0905.pdf
• Recommended Practices
  https://www.cisa.gov/uscert/ncas/tips/ST04-014
• Recommended Practices
  https://www.cisa.gov/news-events/ics-alerts/ics-alert-10-301-01
• Recommended Practices
  https://www.cisa.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf
• Recommended Practices
  https://www.cisa.gov/news-events/news/targeted-cyber-intrusion-detection-and-mitigation-strategies-update-b
• Recommended Practices
  https://www.cisa.gov/secure-our-world/teach-employees-avoid-phishing
• Recommended Practices
  https://www.cisa.gov/news-events/news/avoiding-social-engineering-and-phishing-attacks