CVE-2020-20949 json
Bleichenbacher's attack on PKCS #1 v1.5 padding for RSA in STM32 cryptographic firmware library software expansion for STM32Cube (UM1924).
published 5y ago modified 4mo ago also EUVD-2020-13728
- cvss
- 5.9
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.9%
- EPSS 0.9% chance of exploitation in 30 days, percentile 61%
- public exploits
- 0
- none known
Summary
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 server using the vulnerable library, resulting in remote information disclosure.
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0.94% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
| NVD | 2.0 | 4.3 | AV:N/AC:M/Au:N/C:P/I:N/A:N |
Classification
- Weakness
-
- CWE-327 Use of a Broken or Risky Cryptographic Algorithm
References
-
archiv.infsec.ethz.ch
/education/fs08/secsem/bleichenbacher98.pdf
technical-description, third-party-advisory
-
st.com
/en/embedded-software/x-cube-cryptolib.html
third-party-advisory
-
bi-zone.medium.com
/silence-will-fall-or-how-it-can-take-2-years-to-get-your-vuln-registered-e6134846f5bb
technical-description, third-party-advisory
Sources
- CVE List CVE-2020-20949
- NVD CVE-2020-20949
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