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TI-2021-21546 Aliases CVE-2021-46878GHSA-r3hq-4h29-qfq9

An issue was discovered in Treasure Data Fluent Bit 1.7.1, erroneous parsing in…

Priority HIGH 69CWE-843Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-843 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.0035 28th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:treasuredata:fluent_bit:1.7.1:*:*:*:*:*:*:*1.7.1VulnerableFluentBit
  • cpe:2.3:a:treasuredata:fluent_bit:1.7.1:*:*:*:*:*:*:* Versions 1.7.1 Vulnerable ·FluentBit

Remediation

No fixed version listed by the sources yet.

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-46878
  2. 2026-10-03 Alias added: GHSA-r3hq-4h29-qfq9

References

Exploit 1

Patch 1

  • TI-2024-17419 fluent-bit 2.2.2 contains a Use-After-Free vulnerability in /fluent-bit/plugins/custom_calyptia/calyptia.c. CVSS 3.1HIGH 7.5
  • TI-2024-15728 In Fluent Bit 2.1.8 through 2.2.1, a NULL pointer dereference can be caused via an… CVSS 3.1HIGH 7.5
  • TI-2024-04026 Fluent Bit Memory Corruption Vulnerability CVSS 3.1CRITICAL 9.8
  • TI-2021-21547 An issue was discovered in Treasure Data Fluent Bit 1.7.1, a wrong variable is used to… CVSS 3.1HIGH 7.8
  • TI-2025-21098 An issue in fluent-bit v.3.7.2 allows a local attacker to cause a denial of service via… CVSS 3.1MEDIUM 5.5
  • TI-2025-21097 An issue in fluent-bit v.3.7.2 allows a local attacker to cause a denial of service via the function consume_event. CVSS 3.1MEDIUM 5.5
See all 17 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences