{"id":"CVE-2026-61633","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-61633","generatedAt":"2026-10-28T00:53:09.055Z","title":"A zero-length topic followed by trailing data can leave buf.curpos unchanged while topic_count continues to increase, allowing a malicious MQTT broker to hang a connecting MQTT 3.1.1 client, consume CPU and memory, and repeatedly deny service when…","description":"NanoMQ is an MQTT broker. Prior to 0.24.14, the NanoMQ client function nni_mqtt_msg_decode_unsubscribe() in nng/src/supplemental/mqtt/mqtt_codec.c does not handle a failed read_uint16() while counting topics in a malformed UNSUBSCRIBE packet. A zero-length topic followed by trailing data can leave buf.curpos unchanged while topic_count continues to increase, allowing a malicious MQTT broker to hang a connecting MQTT 3.1.1 client, consume CPU and memory, and repeatedly deny service when automatic reconnection is enabled. The broker-side nmq_unsubinfo_decode path is not affected. This issue is fixed in version 0.24.14.","published":"2026-09-18T17:16:58.000Z","lastModified":"2026-09-18T18:17:09.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":2,"severity":"LOW","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:L"},"cwe":["CWE-835"],"affected":[],"epss":{"score":0.00338,"percentile":0.27048,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.34%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/nanomq/NanoNNG/commit/fa8d859bb39841e46cfc6cce280d242bd782ad3d","source":"security-advisories@github.com"},{"url":"https://github.com/nanomq/NanoNNG/pull/1518","source":"security-advisories@github.com"},{"url":"https://github.com/nanomq/nanomq/releases/tag/0.24.14","source":"security-advisories@github.com"},{"url":"https://github.com/nanomq/nanomq/security/advisories/GHSA-m7mp-rr3v-hmhr","source":"security-advisories@github.com"},{"url":"https://github.com/nanomq/nanomq/security/advisories/GHSA-m7mp-rr3v-hmhr","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-61633","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."}