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Fencer Vulns
high 7.5

CVE-2021-27186 json

Fluent Bit 1.6.10 has a NULL pointer dereference when an flb_malloc return value is not validated by flb_avro.c or http_server/api/v1/metri…

published 2021-02-10 5 y ago modified 2026-09-08 2 mo ago also BIT-fluent-bit-2021-27186 , EUVD-2021-13952

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.0%
EPSS 2.0% chance of exploitation in 30 days, percentile 81%
public exploits
0
none known

Summary

Fluent Bit 1.6.10 has a NULL pointer dereference when an flb_malloc return value is not validated by flb_avro.c or http_server/api/v1/metrics.c.

Patch / fix

  • bitnami fluent-bit 1.6.11

Exploit prediction

2.01% chance of exploitation in the next 30 days, higher than 81% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/fluent/fluent-bit/pull/3045 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/fluent/fluent-bit/issues/3044 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami fluent-bit
>=1.6.10, <1.6.11
1.6.11

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.