← Vulnerability feed

Vulnerability record · CVE-2020-35963 · published 3 January 2021

CVE-2020-35963: Treasuredata fluent bit out-of-bounds write vulnerability

Treasuredata · Fluent Bit

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.

7.8 CVSS 3.1 High EPSS 1.3% · top 30.2% CWE-787 · Out-of-bounds write
7.8CVSS 3.1 base score, v2 6.8
1.3%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
6References, 2 tagged exploit
17 Jun 2026Last modified by NVD

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.

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=27261 ExploitIssue TrackingThird Party Advisory
https://fluentbit.io/announcements/v1.6.4/ Release NotesVendor Advisory
https://github.com/fluent/fluent-bit/commit/cadff53c093210404aed01c4cf586adb8caa07af PatchThird Party Advisory
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=27261 ExploitIssue TrackingThird Party Advisory
https://fluentbit.io/announcements/v1.6.4/ Release NotesVendor Advisory
https://github.com/fluent/fluent-bit/commit/cadff53c093210404aed01c4cf586adb8caa07af PatchThird Party Advisory

Track CVE-2020-35963 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2024-4323Treasuredata fluent bit heap-based buffer overflow vulnerabilityA memory corruption vulnerability in Fluent Bit versions 2.0.7 thru 3.0.3. This issue lies in the embedded http server’s parsing of trace requests an…EPSS 27%9.8CVE-2021-36088Treasuredata fluent bit double free vulnerabilityFluent Bit (aka fluent-bit) 1.7.0 through 1.7.4 has a double free in flb_free (called from flb_parser_json_do and flb_parser_do).EPSS 2.4%9.1CVE-2025-12977Treasuredata fluent bit vulnerabilityFluent Bit in_http, in_splunk, and in_elasticsearch input plugins fail to sanitize tag_key inputs. An attacker with network access or the ability to …EPSS 0.73%8.8CVE-2025-12970Treasuredata fluent bit classic buffer overflow vulnerabilityThe extract_name function in Fluent Bit in_docker input plugin copies container names into a fixed size stack buffer without validating length. An at…EPSS 1.0%7.8CVE-2021-46878Treasuredata fluent bit type confusion vulnerabilityAn 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 inte…EPSS 0.35%7.8CVE-2021-46879Treasuredata fluent bit out-of-bounds write vulnerabilityAn 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_msgpa…EPSS 0.38%7.5CVE-2024-50608Treasuredata fluent bit null pointer dereference vulnerabilityAn issue was discovered in Fluent Bit 3.1.9. When the Prometheus Remote Write input plugin is running and listening on an IP address and port, one ca…EPSS 1.1%7.5CVE-2024-50609Treasuredata fluent bit null pointer dereference vulnerabilityAn issue was discovered in Fluent Bit 3.1.9. When the OpenTelemetry input plugin is running and listening on an IP address and port, one can send a p…EPSS 1.1%

Source: NIST National Vulnerability Database (record CVE-2020-35963), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.