{"id":"CVE-2026-47275","state":"PUBLISHED","title":"nanomq NULL Pointer Dereference in MQTTv5 Client CONNECT Decoder Leading to Remote DoS","description":"In nanomq versions 0.24.11 and earlier, a NULL pointer dereference in `nni_mqttv5_msg_decode_connect()` allows a malicious MQTT broker to crash any connecting NanoMQ MQTTv5 client (including bridge mode) with a single packet, causing remote denial of service via SIGSEGV. In `nni_mqttv5_msg_decode_connect()` (`mqtt_codec.c:1863`), the code iterates over CONNECT properties using variable `prop` when it should use `will_prop`. When a CONNECT packet has no connect-level properties (`prop == NULL`) but has will properties (`will_prop != NULL`), dereferencing `prop->next` causes SIGSEGV at address `0x38` (NULL + `offsetof(property, next)`).\n\nThis affects both `nanomq_cli` and **NanoMQ bridge mode** (Core component), as both use the same `mqtt_client.c` receive path. This can lead to remote DoS if a malicious MQTT broker can crash the client process with a single 35-byte packet and persistent DoS if auto-reconnect causes infinite crash loop.","publishedAt":"2026-07-20T16:43:03.704Z","updatedAt":"2026-07-20T18:56:28.995Z","severity":{"score":2.6,"label":"Low","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L","source":"GitHub_M"},"assigner":"GitHub_M","products":["nanomq nanomq"],"affected":[{"vendor":"nanomq","product":"nanomq","versions":[{"version":"<= 0.24.11","status":"affected"}]}],"references":["https://github.com/nanomq/nanomq/security/advisories/GHSA-52qr-3v49-wmx6"],"weaknesses":["CWE-476"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/47xxx/CVE-2026-47275.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-47275","state":"PUBLISHED","datePublished":"2026-07-20T16:43:03.704Z","dateUpdated":"2026-07-20T18:56:28.995Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-18T23:03:37.230Z"},"containers":{"cna":{"title":"nanomq NULL Pointer Dereference in MQTTv5 Client CONNECT Decoder Leading to Remote DoS","descriptions":[{"lang":"en","value":"In nanomq versions 0.24.11 and earlier, a NULL pointer dereference in `nni_mqttv5_msg_decode_connect()` allows a malicious MQTT broker to crash any connecting NanoMQ MQTTv5 client (including bridge mode) with a single packet, causing remote denial of service via SIGSEGV. In `nni_mqttv5_msg_decode_connect()` (`mqtt_codec.c:1863`), the code iterates over CONNECT properties using variable `prop` when it should use `will_prop`. When a CONNECT packet has no connect-level properties (`prop == NULL`) but has will properties (`will_prop != NULL`), dereferencing `prop->next` causes SIGSEGV at address `0x38` (NULL + `offsetof(property, next)`).\n\nThis affects both `nanomq_cli` and **NanoMQ bridge mode** (Core component), as both use the same `mqtt_client.c` receive path. This can lead to remote DoS if a malicious MQTT broker can crash the client process with a single 35-byte packet and persistent DoS if auto-reconnect causes infinite crash loop."}],"affected":[{"vendor":"nanomq","product":"nanomq","versions":[{"version":"<= 0.24.11","status":"affected"}]}],"references":[{"url":"https://github.com/nanomq/nanomq/security/advisories/GHSA-52qr-3v49-wmx6","name":"https://github.com/nanomq/nanomq/security/advisories/GHSA-52qr-3v49-wmx6","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":2.6,"baseSeverity":"LOW","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-476","lang":"en","description":"CWE-476: NULL Pointer Dereference","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-20T16:43:03.704Z"},"source":{"advisory":"GHSA-52qr-3v49-wmx6","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/nanomq/nanomq/security/advisories/GHSA-52qr-3v49-wmx6","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-20T18:56:22.265285Z","id":"CVE-2026-47275","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-20T18:56:28.995Z"}}]}}}