{"id":"CVE-2019-9749","details":"An issue was discovered in the MQTT input plugin in Fluent Bit through 1.0.4. When this plugin acts as an MQTT broker (server), it mishandles incoming network messages. After processing a crafted packet, the plugin's mqtt_packet_drop function (in /plugins/in_mqtt/mqtt_prot.c) executes the memmove() function with a negative size parameter. That leads to a crash of the whole Fluent Bit server via a SIGSEGV signal.","modified":"2026-07-08T19:01:54.784749Z","published":"2019-03-13T19:29:00.297Z","references":[{"type":"EVIDENCE","url":"https://github.com/fluent/fluent-bit/issues/1135"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/fluent/fluent-bit","events":[{"introduced":"0"},{"last_affected":"de308c70d31e13bfaf86e979e0f74bced6b2e236"}],"database_specific":{"source":"CPE_RANGE","cpe":"cpe:2.3:a:treasuredata:fluent_bit:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"0"},{"last_affected":"1.0.4"}]}}],"versions":["v1.0.4","v1.0.3","v1.0.2","v1.0.1","v1.0.0","v0.14.0","v0.13.0","0.13-dev-0.18","0.13-dev-0.17","0.13-dev-0.16","0.13-dev-0.15","0.13-dev-0.14","0.13-dev-0.13","0.13-dev-0.12","0.13-dev-0.11","0.13-dev-0.10","0.13-dev-0.9","0.13-dev-0.4","v0.12.4","v0.12.3","v0.12.2","v0.12.1","v0.12.0","v0.11.0","v0.10.0","v0.9.0","v0.8.2","v0.8.1","v0.8.0","v0.7.0","v0.6.0","v0.5.1","v0.5","v0.4","v0.3"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2019-9749.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}