{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-87121 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-87121 is a critical memory corruption vulnerability in lwIP TCP/IP Stack MQTT, published on 22 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-87121 and fix it if it is affected.\n\nWhat it is: CVE-2026-87121 is a critical memory corruption vulnerability in lwIP TCP/IP Stack MQTT, published on 22 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-87121 in the wild and no public exploit code.\n\nAffected product: lwIP TCP/IP Stack MQTT. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-87121/ (Markdown: https://insights.sbomify.com/CVE-2026-87121/index.md)","id":"CVE-2026-87121","markdown":"https://insights.sbomify.com/CVE-2026-87121/index.md","name":"CVE-2026-87121","record":{"aliases":["DEBIAN-CVE-2026-87121","GHSA-h8q6-7rjx-3m2r","UBUNTU-CVE-2026-87121"],"analysis":{"component_type":"library","fix_type":"patch","impacts":["code_execution"],"network_reachable":"yes","non_default_config":false,"product_category":"lwIP TCP/IP Stack","requires_auth":"none","summary":"An out-of-bounds write in the lwIP MQTT client allows attackers to achieve full code execution on affected devices.","user_interaction":"not_required","vuln_class":"memory_corruption"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"icscert","cpe":[],"cvss":{"score":9.3,"severity":"critical","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-787","name":"Out-of-bounds Write"}],"description":"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.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Out-of-bounds write in lwIP TCP/IP Stack MQTT Client Application","id":"CVE-2026-87121","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"memory_corruption","year":"2026"},"n_packages":0,"n_references":3,"next":{"headline":"hbs vulnerable to Denial of Service via unhandled exception in async helper output escaping","id":"CVE-2026-87123"},"packages":[],"prev":{"headline":"Auth bypass in mpp","id":"CVE-2026-87119"},"products":["TCP/IP Stack MQTT"],"published":"2026-09-22","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-09-22","vendors":["lwIP"]},"summary":"An out-of-bounds write in the lwIP MQTT client allows attackers to achieve full code execution on affected devices.","url":"https://insights.sbomify.com/CVE-2026-87121/"}