CVE-2021-46879

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2023-04-11 · updated 2026-06-17
Weakness: CWE-787

Description

An issue was discovered in Treasure Data Fluent Bit 1.7.1, a wrong variable is used to get the msgpack data resulting in a heap overflow in flb_msgpack_gelf_value_ext. An attacker can craft a malicious file and tick the victim to open the file with the software, triggering a heap overflow and execute arbitrary code on the target system.

Affected products

FluentBit Fluent Bit: 1.7.1

References

https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=26851
https://github.com/fluent/fluent-bit/pull/3100
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=26851
https://github.com/fluent/fluent-bit/pull/3100

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