Cyber Resilience

CVE-2020-20949

Medium

Published: 20 January 2021

Published
20 January 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.0059 69.7th percentile
Risk Priority 12 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2020-20949 is a medium-severity Use of a Broken or Risky Cryptographic Algorithm (CWE-327) vulnerability in St Stm32Cubef0. Its CVSS base score is 5.9 (Medium).

Operationally, ranked in the top 30.3% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

Bleichenbacher's attack on PKCS #1 v1.5 padding for RSA in STM32 cryptographic firmware library software expansion for STM32Cube (UM1924). The vulnerability can allow one to use Bleichenbacher's oracle attack to decrypt an encrypted ciphertext by making successive queries to the…

more

server using the vulnerable library, resulting in remote information disclosure.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

st
stm32cubef0
all versions
st
stm32cubef1
all versions
st
stm32cubef2
all versions
st
stm32cubef3
all versions
st
stm32cubef4
all versions
st
stm32cubef7
all versions
st
stm32cubeg0
all versions
st
stm32cubeg4
all versions
st
stm32cubeh7
all versions
st
stm32cubeide
all versions
+12 more product configuration(s) — see NVD for full list

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-327

Contacts with security groups provide timely information on broken or risky cryptographic algorithms, reducing the likelihood of their selection and use.

addresses: CWE-327

Ongoing education and sharing of recommended practices helps organizations identify and migrate away from broken or risky cryptographic algorithms.

addresses: CWE-327

Cross-organization threat feeds commonly include advances in cryptanalysis and active exploits against weak or broken algorithms, allowing organizations to deprecate them proactively.

addresses: CWE-327

Capital planning and funding allow selection and ongoing support of strong cryptographic algorithms rather than weak or broken ones.

addresses: CWE-327

Risk updates surface newly-broken or risky cryptographic algorithms as threat intelligence and computing advances evolve, enabling timely replacement.

addresses: CWE-327

Scanners flag use of broken or weak cryptographic algorithms via known-vulnerability databases.

addresses: CWE-327

Enforces approved cryptographic algorithms for each use case, blocking use of broken or risky algorithms.

addresses: CWE-327

Flaw remediation replaces broken or risky cryptographic algorithms once safer implementations are released by vendors.

References