CVE-2020-12403

CRITICALNVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-24. NVD baseline CVSS 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 2%CVSS: 9.1Exploit: NoneExposed: 0

A fix is available — apply it.

A flaw was found in the way CHACHA20-POLY1305 was implemented in NSS in versions before 3.55. When using multi-part Chacha20, it could cause out-of-bounds reads. This issue was fixed by explicitly disabling multi-part ChaCha20 (which was not functioning correctly) and strictly enforcing tag length. The highest threat from this vulnerability is to confidentiality and system availability.

CVSS v3
9.1
EG Score
9.1(medium)
EPSS
72.3%
KEV
Not listed

Published

May 27, 2021

Last Modified

November 21, 2024

Advisory Details (3)

Auto-updated Jul 18, 2026
Patch available. Sources: redhat.
generic

NetApp Product Security

https://security.netapp.com/advisory/ntap-20230324-0006/
generic Patch Available

[SECURITY] [DLA 3327-1] nss security update

https://lists.debian.org/debian-lts-announce/2023/02/msg00021.html
redhat Patch Available

1868931 – (CVE-2020-12403) CVE-2020-12403 nss: CHACHA20-POLY1305 decryption with undersized tag leads to out-of-bounds read

Affected: Red Hat Enterprise Linux 7

https://bugzilla.redhat.com/show_bug.cgi?id=1868931

Vendor Advisories for CVE-2020-12403(6)

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

Patch Availability(6)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatnss-softokn-0:3.44.0-9.el7_72021-03-30redhat
redhatopenshiftdo/odo-init-image-rhel7:1.1.3-22021-03-22redhat
redhatnss-softokn-0:3.36.0-7.el7_62021-03-16redhat
redhatnss-softokn-0:3.28.3-10.el7_42021-03-09redhat
redhatnss-0:3.53.1-17.el8_32021-02-16redhat
redhatnss-util-0:3.53.1-1.el7_92020-09-29redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 12× in last 7d / 43× 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.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2020-12403?
CVE-2020-12403 is a critical vulnerability published on May 27, 2021. A flaw was found in the way CHACHA20-POLY1305 was implemented in NSS in versions before 3.55. When using multi-part Chacha20, it could cause out-of-bounds reads. This issue was fixed by explicitly disabling multi-part ChaCha20 (which was not functioning correctly) and strictly enforcing tag length.…
When was CVE-2020-12403 disclosed?
CVE-2020-12403 was first published in the National Vulnerability Database on May 27, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-12403 actively exploited?
CVE-2020-12403 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 72.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2020-12403?
CVE-2020-12403 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2020-12403?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-12403, 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.

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