How severe is CVE-2021-46878?

CVE-2021-46878 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-46878 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-46878?

CVE-2021-46878 affects Treasuredata Fluent Bit. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-46878?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-46878 published?

CVE-2021-46878 was published on 2023-04-11 and last updated on 2026-06-17.

CVE-2021-46878

CVE-2021-46878 is a high-severity vulnerability in Treasuredata Fluent Bit with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-843.

Key facts

Severity: High (CVSS 3.x base score 7.8)
EPSS exploit prediction: 0% (27th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-843
Affected product: Treasuredata Fluent Bit
Published: 2023-04-11
Last modified: 2026-06-17

Description

An issue was discovered in Treasure Data Fluent Bit 1.7.1, erroneous parsing in flb_pack_msgpack_to_json_format leads to type confusion bug that interprets whatever is on the stack as msgpack maps and arrays, leading to use-after-free. This can be used by an attacker to craft a specially craft file and trick the victim opening it using the affect software, triggering use-after-free and execute arbitrary code on the target system.

Frequently asked questions

What is CVE-2021-46878?: An issue was discovered in Treasure Data Fluent Bit 1.7.1, erroneous parsing in flb_pack_msgpack_to_json_format leads to type confusion bug that interprets whatever is on the stack as msgpack maps and arrays, leading to use-after-free. This can be used by an attacker to craft a specially craft file and trick the victim opening it using the affect software, triggering use-after-free and execute arbitrary code on the target system.
How severe is CVE-2021-46878?: CVE-2021-46878 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-46878 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-46878?: CVE-2021-46878 affects Treasuredata Fluent Bit. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-46878?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-46878 published?: CVE-2021-46878 was published on 2023-04-11 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:treasuredata:fluent_bit:1.7.1:*:*:*:*:*:*:*

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