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.
Conclusion & alert: CVE-2020-35963 is rated High Exploit Risk (70.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.31%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.38% | 1.31% | +0.93% |
| 2 | 2025-03-30 | 0.54% | 0.38% | -0.16% |
| 3 | 2025-03-29 | — | 0.54% | — |
Full EPSS history (10 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.8 | 3.1 | HIGH |
|
1.8 | 5.9 | [email protected] |
| 6.8 | 2.0 | MEDIUM |
|
8.6 | 6.4 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2020-35963 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| treasuredata | fluent_bit | < 1.6.4 | cpe:2.3:a:treasuredata:fluent_bit:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=27261 | Exploit Issue Tracking Third Party Advisory |
| https://fluentbit.io/announcements/v1.6.4/ | Release Notes Vendor Advisory |
| https://github.com/fluent/fluent-bit/commit/cadff53c093210404aed01c4cf586adb8caa07af | Patch Third Party Advisory |