CVE-2021-27186
Fluent Bit 1.6.10 has a NULL pointer dereference when an flb_malloc return value is not validated...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2021-27186- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-476
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2021-27186- Updated
- 2026-11-02
EUVDEUVD-2021-13952 No score
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.
- Record
EUVD-2021-13952- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-gjm8-qc7w-3xxp
Fluent Bit 1.6.10 has a NULL pointer dereference when an flb_malloc return value is not validated...
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.
- Record
GHSA-gjm8-qc7w-3xxp- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-476
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2021-27186- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVBIT-fluent-bit-2021-27186 No score
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.
- Record
BIT-fluent-bit-2021-27186- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
fluent-bitBitnami |
1.6.10 up to 1.6.11 | 1.6.11 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-27186 is a high vulnerability (CVSS 7.5) in Treasuredata Fluent Bit, published February 10, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.99%, the 80th percentile. Fixed in fluent-bit 1.6.11.