CVE-2019-9749 json
An issue was discovered in the MQTT input plugin in Fluent Bit through 1.0.4.
published 2019-03-13 7 y ago modified 2026-06-17 4 mo ago also EUVD-2019-19112
- cvss
- 7.5
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.7%
- EPSS 1.7% chance of exploitation in 30 days, percentile 76%
- public exploits
- 0
- none known
Summary
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.
Exploit prediction
1.66% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/fluent/fluent-bit/issues/1135 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVD | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:N/I:N/A:P |
Classification
- Weakness
-
- CWE-681 Incorrect Conversion between Numeric Types
References
-
github.com
/fluent/fluent-bit/issues/1135
exploit, third-party-advisory
Sources
- CVE List CVE-2019-9749
- NVD CVE-2019-9749
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