{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-54412","assignerOrgId":"309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c","state":"PUBLISHED","assignerShortName":"TuranSec","dateReserved":"2026-06-13T16:39:46.122Z","datePublished":"2026-06-14T17:26:36.740Z","dateUpdated":"2026-11-05T12:44:48.838Z"},"containers":{"cna":{"providerMetadata":{"orgId":"309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c","shortName":"TuranSec","dateUpdated":"2026-11-05T12:44:48.838Z"},"title":"MQTT-C Heap Out-of-Bounds Read and Integer Underflow in mqtt_unpack_publish_response()","datePublic":"2026-06-14T17:26:00.000Z","problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-125","description":"CWE-125 Out-of-bounds Read","type":"CWE"}]},{"descriptions":[{"lang":"en","cweId":"CWE-191","description":"CWE-191 Integer Underflow (Wrap or Wraparound)","type":"CWE"}]}],"impacts":[{"descriptions":[{"lang":"en","value":"A remote attacker controlling an MQTT broker, or able to inject one PUBLISH packet into an unencrypted MQTT session to which a victim has subscribed, can crash a subscribed MQTT-C client by sending a crafted PUBLISH packet whose topic_name_size exceeds the remaining_length field. The vulnerable client advances the parse pointer into unmapped heap memory, causing an out-of-bounds read that may expose adjacent heap bytes. It then calculates application_message_size using unsigned subtraction, causing an integer underflow to a value near 2^32, and passes that value to memmove(), crashing the process. IoT and embedded devices using MQTT-C with shared, untrusted, or compromised brokers are exposed to unauthenticated denial of service."}]}],"affected":[{"vendor":"LiamBindle","product":"MQTT-C","collectionURL":"https://github.com/LiamBindle/MQTT-C","repo":"https://github.com/LiamBindle/MQTT-C","programFiles":["src/mqtt.c"],"programRoutines":[{"name":"mqtt_unpack_publish_response"}],"versions":[{"status":"affected","version":"0","lessThan":"1.1.7","versionType":"semver"},{"status":"unaffected","version":"1.1.7","versionType":"semver"}],"defaultStatus":"unknown"}],"descriptions":[{"lang":"en","value":"LiamBindle MQTT-C versions prior to 1.1.7 contain a heap-based out-of-bounds read and integer underflow in the mqtt_unpack_publish_response() function in src/mqtt.c. A remote unauthenticated attacker controlling an MQTT broker, or capable of injecting MQTT traffic into an unencrypted session, can crash a subscribed MQTT-C client and potentially disclose adjacent heap memory by sending a single crafted PUBLISH packet.","supportingMedia":[{"type":"text/html","base64":false,"value":"<p>LiamBindle MQTT-C versions prior to 1.1.7 contain a heap-based out-of-bounds read and integer underflow in the mqtt_unpack_publish_response() function in src/mqtt.c. A remote unauthenticated attacker controlling an MQTT broker, or capable of injecting MQTT traffic into an unencrypted session, can crash a subscribed MQTT-C client and potentially disclose adjacent heap memory by sending a single crafted PUBLISH packet.</p>"}]}],"references":[{"url":"https://github.com/LiamBindle/MQTT-C","name":"LiamBindle/MQTT-C upstream repository","tags":["product"]},{"url":"https://github.com/LiamBindle/MQTT-C/blob/v1.1.6/src/mqtt.c#L1334","name":"Vulnerable mqtt_unpack_publish_response() in src/mqtt.c (v1.1.6)","tags":["product"]},{"url":"https://github.com/LiamBindle/MQTT-C/pull/208","name":"Fix out-of-bounds read and integer underflow in PUBLISH parsing","tags":["patch"]},{"url":"https://github.com/LiamBindle/MQTT-C/releases/tag/v1.1.7","name":"MQTT-C v1.1.7 release","tags":["release-notes","patch"]},{"url":"https://cwe.mitre.org/data/definitions/125.html","name":"CWE-125: Out-of-bounds Read","tags":["technical-description"]},{"url":"https://cwe.mitre.org/data/definitions/191.html","name":"CWE-191: Integer Underflow (Wrap or Wraparound)","tags":["technical-description"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"A malicious MQTT broker, or a network attacker capable of injecting a single MQTT PUBLISH packet into an unencrypted session to which the victim client has subscribed, sends a crafted packet with topic_name_size = 0xFFFF and remaining_length = 7 to crash an MQTT-C-based client process and potentially disclose adjacent heap bytes."}],"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"LOW","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subAvailabilityImpact":"NONE","exploitMaturity":"PROOF_OF_CONCEPT","Safety":"NOT_DEFINED","Automatable":"YES","Recovery":"NOT_DEFINED","valueDensity":"DIFFUSE","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"HIGH","baseScore":7.8,"vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/AU:Y/V:D"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"NONE","availabilityImpact":"HIGH","baseSeverity":"HIGH","baseScore":8.2,"vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H"}}],"credits":[{"lang":"en","value":"Saidakbarxon Maxsudxonov","type":"finder"}],"source":{"discovery":"EXTERNAL"},"x_generator":{"engine":"Vulnogram 1.0.5"},"x_author":"Saidakbarxon Maxsudxonov","x_assigner_notes":"The vulnerable mqtt_unpack_publish_response() implementation was verified at the v1.1.6 release tag. The function performs a remaining_length >= 4 fixed-header sanity check but trusts the broker-controlled 16-bit topic_name_size field as a pointer offset and as a subtrahend in the unsigned application_message_size calculation. This can result in an out-of-bounds read and integer underflow, followed by a potentially oversized memmove() operation and process crash. The upstream fix is referenced in PR #208 and MQTT-C v1.1.7 release notes. Versions prior to 1.1.7 are affected; version 1.1.7 is considered unaffected. Mitigation: validate that topic_name_size + 2 + (qos_level > 0 ? 2 : 0) does not exceed remaining_length before using topic_name_size as a pointer offset or subtrahend, or migrate to a maintained MQTT client library such as Eclipse Paho MQTT C or libmosquitto."},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-15T17:01:08.771614Z","id":"CVE-2026-54412","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-06-15T17:01:16.924Z"}}]}}