CVE-2020-20949

MEDIUMNVD 5.95.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.9 under NVD CVSS v3. EPSS exploit probability: 0.9%, top 43% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
5.9
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 5.9Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
5.9
EG Score
5.9(medium)
EG Risk
31(Track)
EG Risk 31/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity59% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
56.5%
KEV
Not listed

Published

January 20, 2021

Last Modified

July 9, 2026

Advisory Details (1)

Auto-updated Jul 9, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic🔴 Active Exploitation

Silence Will Fall (Or How It Can Take 2 Years to Get Your Vuln Registered) | by BI.ZONE | Medium

https://bi-zone.medium.com/silence-will-fall-or-how-it-can-take-2-years-to-get-your-vuln-registered-e6134846f5bb

Vendor Advisories for CVE-2020-20949(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 51× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 102 total refreshes for this CVE.

  1. 2026-07-23 01:50 UTCEG score recompute
  2. 2026-07-22 22:36 UTCEG score recompute
  3. 2026-07-22 14:05 UTCEPSS rescore
  4. 2026-07-21 15:22 UTCEPSS rescore
  5. 2026-07-21 15:22 UTCEPSS rescore
  6. 2026-07-20 17:04 UTCEPSS rescore
  7. 2026-07-20 17:04 UTCEPSS rescore
  8. 2026-07-19 14:28 UTCEPSS rescore
  9. 2026-07-19 02:26 UTCEPSS rescore
  10. 2026-07-19 02:26 UTCEPSS rescore
  11. 2026-07-18 10:02 UTCEPSS rescore
  12. 2026-07-16 16:59 UTCEPSS rescore
  13. 2026-07-15 16:55 UTCEPSS rescore
  14. 2026-07-15 01:57 UTCEPSS rescore
  15. 2026-07-13 22:27 UTCEPSS rescore
  16. 2026-07-13 22:27 UTCEPSS rescore
  17. 2026-07-13 06:10 UTCEPSS rescore
  18. 2026-07-13 06:10 UTCEPSS rescore
  19. 2026-07-12 05:44 UTCEPSS rescore
  20. 2026-07-11 08:25 UTCEPSS rescore
  21. 2026-07-11 08:25 UTCEPSS rescore
  22. 2026-07-09 19:07 UTCEPSS rescore
  23. 2026-07-09 00:54 UTCNVD updateCVSS v3 → 5.9 · severity → MEDIUM
  24. 2026-07-09 00:13 UTCMITRE cvelistV5
  25. 2026-07-08 15:12 UTCEPSS rescore
Show 75 more
  1. 2026-07-07 13:43 UTCEPSS rescore
  2. 2026-07-07 13:43 UTCEPSS rescore
  3. 2026-07-06 16:25 UTCEPSS rescore
  4. 2026-07-06 16:25 UTCEPSS rescore
  5. 2026-07-06 02:21 UTCEPSS rescore
  6. 2026-07-06 02:21 UTCEPSS rescore
  7. 2026-07-05 17:59 UTCNVD updateCVSS v3 → 5.9 · severity → MEDIUM
  8. 2026-07-05 16:09 UTCMITRE cvelistV5
  9. 2026-07-05 02:27 UTCEPSS rescore
  10. 2026-07-05 00:28 UTCNVD updateCVSS v3 → 5.9 · severity → MEDIUM
  11. 2026-07-04 23:57 UTCMITRE cvelistV5
  12. 2026-07-04 06:29 UTCEPSS rescore
  13. 2026-07-04 06:28 UTCEPSS rescore
  14. 2026-07-01 15:03 UTCEPSS rescore
  15. 2026-06-30 23:20 UTCEPSS rescore
  16. 2026-06-30 23:20 UTCEPSS rescore
  17. 2026-06-29 14:04 UTCEPSS rescore
  18. 2026-06-28 14:05 UTCEPSS rescore
  19. 2026-06-28 04:54 UTCEPSS rescore
  20. 2026-06-28 04:54 UTCEPSS rescore
  21. 2026-06-27 03:06 UTCEPSS rescore
  22. 2026-06-25 13:47 UTCEPSS rescore
  23. 2026-06-24 14:03 UTCEPSS rescore
  24. 2026-06-24 14:03 UTCEPSS rescore
  25. 2026-06-23 21:31 UTCEPSS rescore
  26. 2026-06-23 21:31 UTCEPSS rescore
  27. 2026-06-22 14:23 UTCEPSS rescore
  28. 2026-06-22 14:23 UTCEPSS rescore
  29. 2026-06-21 14:54 UTCEPSS rescore
  30. 2026-06-21 14:54 UTCEPSS rescore
  31. 2026-06-21 01:57 UTCEPSS rescore
  32. 2026-06-21 01:57 UTCEPSS rescore
  33. 2026-06-19 19:23 UTCEPSS rescore
  34. 2026-06-18 17:50 UTCEPSS rescore
  35. 2026-06-17 17:50 UTCEPSS rescore
  36. 2026-06-16 17:50 UTCEPSS rescore
  37. 2026-06-16 17:50 UTCEPSS rescore
  38. 2026-06-15 17:46 UTCEPSS rescore
  39. 2026-06-14 23:15 UTCEPSS rescore
  40. 2026-06-13 22:58 UTCEPSS rescore
  41. 2026-06-13 22:58 UTCEPSS rescore
  42. 2026-06-12 23:10 UTCEPSS rescore
  43. 2026-06-11 13:58 UTCEPSS rescore
  44. 2026-06-10 22:16 UTCEPSS rescore
  45. 2026-06-10 22:16 UTCEPSS rescore
  46. 2026-06-10 13:20 UTCEPSS rescore
  47. 2026-06-08 14:15 UTCEPSS rescore
  48. 2026-06-08 14:15 UTCEPSS rescore
  49. 2026-06-07 15:23 UTCEPSS rescore
  50. 2026-06-07 15:23 UTCEPSS rescore
  51. 2026-06-06 13:45 UTCEPSS rescore
  52. 2026-06-06 13:45 UTCEPSS rescore
  53. 2026-06-05 22:45 UTCEPSS rescore
  54. 2026-06-05 22:45 UTCEPSS rescore
  55. 2026-06-05 06:08 UTCEPSS rescore
  56. 2026-06-05 06:08 UTCEPSS rescore
  57. 2026-06-04 13:10 UTCEPSS rescore
  58. 2026-06-04 13:10 UTCEPSS rescore
  59. 2026-06-02 20:11 UTCEPSS rescore
  60. 2026-06-02 20:11 UTCEPSS rescore
  61. 2026-06-01 13:50 UTCEPSS rescore
  62. 2026-06-01 13:50 UTCEPSS rescore
  63. 2026-05-31 22:29 UTCEPSS rescore
  64. 2026-05-31 22:29 UTCEPSS rescore
  65. 2026-05-31 00:15 UTCEPSS rescore
  66. 2026-05-31 00:15 UTCEPSS rescore
  67. 2026-05-29 13:42 UTCEPSS rescore
  68. 2026-05-28 13:43 UTCEPSS rescore
  69. 2026-05-28 13:43 UTCEPSS rescore
  70. 2026-05-27 13:39 UTCEPSS rescore
  71. 2026-05-26 21:51 UTCEG score recompute
  72. 2026-05-26 21:51 UTCGHSA enrichment
  73. 2026-05-26 13:42 UTCEPSS rescore
  74. 2026-05-26 13:42 UTCEPSS rescore
  75. 2026-05-26 07:17 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2020-20949?
CVE-2020-20949 is a medium vulnerability published on January 20, 2021. 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…
When was CVE-2020-20949 disclosed?
CVE-2020-20949 was first published in the National Vulnerability Database on January 20, 2021, with the most recent update on July 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-20949 actively exploited?
CVE-2020-20949 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 56.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2020-20949?
CVE-2020-20949 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2020-20949?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-20949, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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