CVE-2021-36088 json
Fluent 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).
published 2021-07-01 5 y ago modified 2026-09-08 2 mo ago also BIT-fluent-bit-2021-36088 , EUVD-2021-22721
- cvss
- 9.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 2.4%
- EPSS 2.4% chance of exploitation in 30 days, percentile 84%
- public exploits
- 0
- none known
Summary
Fluent 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).
Patch / fix
- bitnami fluent-bit 1.7.5
- github.com/fluent/fluent-bit@22346a7 commit
- github.com/fluent/fluent-bit#3453 pull request
- bugs.chromium.org/p/oss-fuzz/issues/detail?id=33750 advisory
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
- Assessed
- 2 y ago
Exploit prediction
2.38% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- bugs.chromium.org https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=33750 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CISA ADP | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| CNA | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 7.5 | AV:N/AC:L/Au:N/C:P/I:P/A:P |
| OSV | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| bitnami | fluent-bit | >=1.7.0, <1.7.5 |
1.7.5 |
Affected products
- treasuredata fluent_bit
Classification
- Weakness
-
- CWE-415 Double Free
References
-
github.com
/fluent/fluent-bit/commit/22346a74c07ceb90296be872be2d53eb92252a54
patch, third-party-advisory, advisory
-
github.com
/fluent/fluent-bit/pull/3453
patch, third-party-advisory, advisory
-
bugs.chromium.org
/p/oss-fuzz/issues/detail?id=33750
exploit, patch, third-party-advisory, advisory
-
github.com
/google/oss-fuzz-vulns/blob/main/vulns/fluent-bit/OSV-2021-702.yaml
third-party-advisory, advisory
-
nvd.nist.gov
/vuln/detail/CVE-2021-36088
web
Sources
- CVE List CVE-2021-36088
- NVD CVE-2021-36088
- OSV BIT-fluent-bit-2021-36088
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.