In Amazon AWS Firecracker before 0.21.3, and 0.22.x before 0.22.1, the serial console buffer can grow its memory usage without limit when data is sent to the standard input. This can result in a memory leak on the microVM emulation thread, possibly occupying more memory than intended on the host.
Conclusion & alert: CVE-2020-27174 is rated Moderate Risk (57.2/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.72%). Core evidence: EPSS rose +1.16% over the last day, indicating growing attacker interest. Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
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 | 0.56% | 1.72% | +1.16% |
| 2 | 2025-03-30 | 0.67% | 0.56% | -0.11% |
| 3 | 2025-03-29 | — | 0.67% | — |
Full EPSS history (10 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.5 | 3.1 | HIGH |
|
3.9 | 3.6 | [email protected] |
| 5.0 | 2.0 | MEDIUM |
|
10.0 | 2.9 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| amazon | firecracker | < 0.21.3 | cpe:2.3:a:amazon:firecracker:*:*:*:*:*:*:*:* |
| amazon | firecracker | >= 0.22.0, < 0.22.1 | cpe:2.3:a:amazon:firecracker:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| http://www.openwall.com/lists/oss-security/2020/10/23/1 | Third Party Advisory |
| https://github.com/firecracker-microvm/firecracker/issues/2177 | Third Party Advisory |
| https://github.com/firecracker-microvm/firecracker/pull/2178 | Patch Third Party Advisory |
| https://github.com/firecracker-microvm/firecracker/pull/2179 | Patch Third Party Advisory |