STMicroelectronics STM32L4 devices through 2020-10-19 have incorrect access control. The flash read-out protection (RDP) can be degraded from RDP level 2 (no access via debug interface) to level 1 (limited access via debug interface) by injecting a fault during the boot phase.
Conclusion & alert: CVE-2020-27212 is rated Low Risk (39.7/100): CVSS High severity, with low exploitation likelihood (EPSS 0.14%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
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 | 2026-05-04 | 0.23% | 0.14% | -0.09% |
| 2 | 2026-05-03 | 0.10% | 0.23% | +0.14% |
| 3 | 2025-11-21 | — | 0.10% | — |
Full EPSS history (14 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.0 | 3.1 | HIGH |
|
1.0 | 5.9 | [email protected] |
| 4.4 | 2.0 | MEDIUM |
|
3.4 | 6.4 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| st | stm32cubel4_firmware | <= 1.16.0 | cpe:2.3:o:st:stm32cubel4_firmware:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://eprint.iacr.org/2021/640 | Third Party Advisory |
| https://www.aisec.fraunhofer.de/de/das-institut/wissenschaftliche-exzellenz/security-and-trust-in-open-source-security-tokens.html | Third Party Advisory |
| https://www.aisec.fraunhofer.de/en/FirmwareProtection.html | Third Party Advisory |