{"id":"CVE-2026-102464","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-102464","generatedAt":"2026-10-27T23:45:12.294Z","title":"A malicious or compromised MQTT broker can exploit this by sending QoS 2 PUBLISH messages with distinct packet identifiers and withholding the PUBREL responses.","description":"In Eclipse Vert.x versions [4.0.0, 4.5.34] or [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], the Eclipse Vert.x MQTT (vertx-mqtt) MqttClient stores every inbound QoS 2 PUBLISH message received from the broker in an internal map (qos2inbound) while awaiting the corresponding PUBREL packet to complete the QoS 2 handshake. This map has no size limit; the maxInflightQueue option is enforced only on the outbound publish path and does not constrain inbound message retention.\n\n\n\nA malicious or compromised MQTT broker can exploit this by sending QoS 2 PUBLISH messages with distinct packet identifiers and withholding the PUBREL responses. Each incomplete handshake causes the client to retain the full publish message (topic, payload, and metadata) indefinitely, leading to unbounded memory growth in the Vert.x process. This can degrade the MQTT-consuming application or cause out-of-memory termination.\n\n\n\nThe impacted component is io.vertx:vertx-mqtt.","published":"2026-10-15T09:17:15.000Z","lastModified":"2026-10-20T19:28:25.000Z","status":"Analyzed","sourceIdentifier":"emo@eclipse.org","cvss":{"version":"4.0","score":8.2,"severity":"HIGH","vector":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-770"],"affected":["eclipse/vert.x"],"epss":{"score":0.00306,"percentile":0.2315,"date":"2026-10-26","history":[{"date":"2026-10-15","score":0.00282,"percentile":0.19292}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.31%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-15T09:17:15.000Z","detail":{"score":"8.2","severity":"HIGH","publishedAt":"2026-10-15T09:17:15.283Z"},"summary":"New CVE, high severity (CVSS 8.2)."}],"references":[{"url":"https://github.com/vert-x3/vertx-mqtt/security/advisories/GHSA-46xj-5735-6qrp","tags":["Vendor Advisory"],"source":"emo@eclipse.org"},{"url":"https://gitlab.eclipse.org/security/cve-assignment/-/work_items/344","tags":["Issue Tracking","Third Party Advisory"],"source":"emo@eclipse.org"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-102464","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}