How severe is CVE-2020-35963?

CVE-2020-35963 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-2020-35963 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-35963?

CVE-2020-35963 affects Treasuredata Fluent Bit. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-35963?

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-2020-35963 published?

CVE-2020-35963 was published on 2021-01-03 and last updated on 2026-06-17.

CVE-2020-35963

CVE-2020-35963 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-787.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 6.8
EPSS exploit prediction: 1% (67th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Treasuredata Fluent Bit
Published: 2021-01-03
Last modified: 2026-06-17

Description

flb_gzip_compress in flb_gzip.c in Fluent Bit before 1.6.4 has an out-of-bounds write because it does not use the correct calculation of the maximum gzip data-size expansion.

Frequently asked questions

What is CVE-2020-35963?: flb_gzip_compress in flb_gzip.c in Fluent Bit before 1.6.4 has an out-of-bounds write because it does not use the correct calculation of the maximum gzip data-size expansion.
How severe is CVE-2020-35963?: CVE-2020-35963 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-2020-35963 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-35963?: CVE-2020-35963 affects Treasuredata Fluent Bit. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-35963?: 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-2020-35963 published?: CVE-2020-35963 was published on 2021-01-03 and last updated on 2026-06-17.

References

Affected products (1)

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

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