CVE-2020-9818

CRITICALNVD 8.89.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 8.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 4 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 2%CVSS: 8.8Exploit: cisa kev · ssvc activeExposed: 0

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

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 13.5 and iPadOS 13.5, iOS 12.4.7, watchOS 6.2.5. Processing a maliciously crafted mail message may lead to unexpected memory modification or application termination.

CVSS v3
8.8
EG Score
9.0(high)
EG Risk
81(Attend)
EG Risk 81/100SSVC: Attend

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
Severity90% × 45%
Exploitation100% × 40%
Automatability0% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
2%
EPSS %ILE
82%
KEV
⚠ Exploited

Published

June 9, 2020

Last Modified

October 23, 2025

Advisory Details (4)

Auto-updated Jun 2, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa.
cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-9818
generic

About the security content of watchOS 6.2.5 - Apple Support

https://support.apple.com/HT211175
generic

About the security content of iOS 12.4.7 - Apple Support

https://support.apple.com/HT211169
generic

About the security content of iOS 13.5 and iPadOS 13.5 - Apple Support

https://support.apple.com/HT211168

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 58× in last 7d / 223× 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 650 total refreshes for this CVE.

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

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Frequently asked(6)

What is CVE-2020-9818?
CVE-2020-9818 is a critical vulnerability published on June 9, 2020. An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 13.5 and iPadOS 13.5, iOS 12.4.7, watchOS 6.2.5. Processing a maliciously crafted mail message may lead to unexpected memory modification or application termination.
When was CVE-2020-9818 disclosed?
CVE-2020-9818 was first published in the National Vulnerability Database on June 9, 2020, with the most recent update on October 23, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-9818 actively exploited?
Yes. CISA added CVE-2020-9818 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Apple iOS, iPadOS, and watchOS. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2020-9818?
CVE-2020-9818 has a CVSS v3 base score of 8.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2020-9818?
CVE-2020-9818 affects Apple iOS, iPadOS, and watchOS. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2020-9818?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-9818, 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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