CVE-2020-9818

CRITICALNVD 8.89.0
EchelonGraph scoreHIGH confidence

“▲” beside the score: it is higher than NVD's CVSS score.

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. The 9.0 is the floor for confirmed exploitation, not an impact rating: this CVE's impact severity (EG Severity) is CVSS 8.8 HIGH under GitHub Security Advisory CVSS. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: CISA Known Exploited Vulnerabilities catalog, EPSS, GitHub Security Advisory, NVD CVSS v3
Exploited in the wild

Also known asEUVD-2020-30597 (ENISA EUVD) · GHSA-r647-89qj-xwmp (GitHub Security Advisories)Source: ENISA EUVD

9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV) — the reason this is sooner than the SSVC decision on this page at low or medium mission impact
CISA-KEV: ExploitedEPSS PROB: 2.3%CVSS: 8.8Exploit: No code on recordExposed services: Not assessed

The CVE record names the fixed release — apply it.

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
9.0CRITICALhigh confidence
EG Risk
80
EG Risk 80/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity88% × 45%
Impact severity (EG Severity): CVSS 8.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation100% × 40%
Fixed at 100% for a CISA KEV listing: EchelonGraph's rule.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Attend at medium and Act at high mission impact.
Exploitation active (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: The CVE record names the fixed release. Apply it within your standard update timelines at low, sooner than that at medium and as soon as possible at high mission impact.
EPSS PROB
2.3%
EPSS %ILE
83rd
KEV
⚠ Exploited

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.0): severity, escalated by confirmed exploitation. This CVE's 9.0 is the CISA KEV floor for confirmed exploitation, not an impact rating: its impact severity (EG Severity) is CVSS 8.8 HIGH.

EG Severity
8.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
2.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
CISA KEV and EG-KEV Tier 1 (exploited in the wild)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Attend at medium mission impactTrack at low, Attend at medium and Act at high mission impact.CISA BOD 26-04: 3 days & forensic triage if the affected system is publicly exposed; 14 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low, Attend at medium and Act at high mission impact.

The CVE record names the fixed release. Apply it within your standard update timelines at low, sooner than that at medium and as soon as possible at high mission impact.

Exploitation active (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)3 days & forensic triage if the affected system is publicly exposed; 14 days if it is not.

The score's inputs: In CISA KEV yes (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

CISA required action“Apply updates per vendor instructions.”

Quoted verbatim from CISA's Known Exploited Vulnerabilities catalog. CISA directs it at US federal civilian executive branch agencies under Binding Operational Directive (BOD) 26-04, which replaced BOD 22-01 on 10 June 2026; it is not EchelonGraph's advice. CISA's notes: https://nvd.nist.gov/vuln/detail/CVE-2020-9818

Published

June 9, 2020

Last Modified

October 23, 2025

Advisory Details (4)

Auto-updated Nov 9, 2026
⚠️ Actively exploited (CISA KEV, CISA Vulnrichment). Fix named in the CVE record. Sources: cisa.
CISA🔴 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
Web page

About the security content of watchOS 6.2.5 - Apple Support

https://support.apple.com/HT211175
Web page

About the security content of iOS 12.4.7 - Apple Support

https://support.apple.com/HT211169
Web page

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 0× in last 7d / 0× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

  1. 2026-11-12 18:45 UTCEchelonGraph re-scored
  2. 2026-11-12 18:45 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub severity MODERATE · GitHub CVSS 8.8
  3. 2026-11-12 16:29 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  4. 2026-11-11 17:34 UTCEchelonGraph re-scored
  5. 2026-11-11 17:34 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub severity MODERATE · GitHub CVSS 8.8
  6. 2026-11-11 16:31 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  7. 2026-11-10 16:34 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  8. 2026-11-10 16:24 UTCEchelonGraph re-scored
  9. 2026-11-10 16:24 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub severity MODERATE · GitHub CVSS 8.8
  10. 2026-11-09 16:29 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  11. 2026-11-09 15:12 UTCEchelonGraph re-scored
  12. 2026-11-09 15:12 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub severity MODERATE · GitHub CVSS 8.8
  13. 2026-11-08 16:32 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  14. 2026-11-08 14:02 UTCEchelonGraph re-scored
  15. 2026-11-08 14:02 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub severity MODERATE · GitHub CVSS 8.8
  16. 2026-11-07 16:33 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  17. 2026-11-07 12:51 UTCEchelonGraph re-scored
  18. 2026-11-07 12:51 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub severity MODERATE · GitHub CVSS 8.8
  19. 2026-11-06 16:30 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  20. 2026-11-06 11:41 UTCEchelonGraph re-scored
  21. 2026-11-06 11:41 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub severity MODERATE · GitHub CVSS 8.8
  22. 2026-11-05 16:30 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  23. 2026-11-05 10:31 UTCEchelonGraph re-scored
  24. 2026-11-05 10:31 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub severity MODERATE · GitHub CVSS 8.8
  25. 2026-11-04 16:29 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
Show 75 more
  1. 2026-11-04 09:21 UTCEchelonGraph re-scored
  2. 2026-11-04 09:21 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub severity MODERATE · GitHub CVSS 8.8
  3. 2026-11-03 16:37 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  4. 2026-11-03 08:10 UTCEchelonGraph re-scored
  5. 2026-11-03 08:10 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub severity MODERATE · GitHub CVSS 8.8
  6. 2026-11-02 16:36 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  7. 2026-11-02 06:58 UTCEchelonGraph re-scored
  8. 2026-11-02 06:58 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub severity MODERATE · GitHub CVSS 8.8
  9. 2026-11-01 16:29 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  10. 2026-11-01 05:48 UTCEchelonGraph re-scored
  11. 2026-11-01 05:48 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  12. 2026-10-31 16:28 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  13. 2026-10-31 04:37 UTCEchelonGraph re-scored
  14. 2026-10-31 04:37 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  15. 2026-10-30 16:29 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  16. 2026-10-30 03:27 UTCEchelonGraph re-scored
  17. 2026-10-30 03:27 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  18. 2026-10-29 16:29 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  19. 2026-10-29 02:16 UTCEchelonGraph re-scored
  20. 2026-10-29 02:16 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  21. 2026-10-28 16:28 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  22. 2026-10-28 01:04 UTCEchelonGraph re-scored
  23. 2026-10-28 01:03 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  24. 2026-10-27 16:28 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  25. 2026-10-26 23:51 UTCEchelonGraph re-scored
  26. 2026-10-26 23:51 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  27. 2026-10-26 16:27 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  28. 2026-10-25 22:40 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  29. 2026-10-25 18:38 UTCEchelonGraph re-scored
  30. 2026-10-25 16:28 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  31. 2026-10-24 21:30 UTCEchelonGraph re-scored
  32. 2026-10-24 21:30 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  33. 2026-10-24 16:28 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  34. 2026-10-23 20:19 UTCEchelonGraph re-scored
  35. 2026-10-23 20:19 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  36. 2026-10-23 16:28 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  37. 2026-10-22 19:08 UTCEchelonGraph re-scored
  38. 2026-10-22 19:07 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  39. 2026-10-22 16:29 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  40. 2026-10-21 17:56 UTCEchelonGraph re-scored
  41. 2026-10-21 17:56 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  42. 2026-10-21 16:28 UTCEPSS rescoreEPSS 2.3% · 83rd percentile
  43. 2026-10-20 16:45 UTCEchelonGraph re-scored
  44. 2026-10-20 16:45 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  45. 2026-10-20 16:28 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
  46. 2026-10-19 16:28 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
  47. 2026-10-19 15:34 UTCEchelonGraph re-scored
  48. 2026-10-19 15:34 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  49. 2026-10-18 16:28 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
  50. 2026-10-18 14:21 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  51. 2026-10-18 09:15 UTCEchelonGraph re-scored
  52. 2026-10-17 16:28 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
  53. 2026-10-17 13:10 UTCEchelonGraph re-scored
  54. 2026-10-17 13:10 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  55. 2026-10-16 16:33 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
  56. 2026-10-16 11:58 UTCEchelonGraph re-scored
  57. 2026-10-16 11:58 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  58. 2026-10-15 16:27 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
  59. 2026-10-15 10:46 UTCEchelonGraph re-scored
  60. 2026-10-15 10:46 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  61. 2026-10-14 16:28 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
  62. 2026-10-14 09:33 UTCEchelonGraph re-scored
  63. 2026-10-14 09:33 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  64. 2026-10-13 16:28 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
  65. 2026-10-13 08:20 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  66. 2026-10-12 19:28 UTCEchelonGraph re-scored
  67. 2026-10-12 16:29 UTCEPSS rescoreEPSS 2.3% · 82nd percentile
  68. 2026-10-12 07:09 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  69. 2026-10-12 02:54 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  70. 2026-10-11 22:39 UTCEchelonGraph re-scored
  71. 2026-10-11 22:39 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  72. 2026-10-11 18:26 UTCEchelonGraph re-scored
  73. 2026-10-11 18:26 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8
  74. 2026-10-11 14:13 UTCEchelonGraph re-scored
  75. 2026-10-11 14:12 UTCGHSA enrichmentGHSA-r647-89qj-xwmp · GitHub CVSS 8.8

Frequently asked(6)

What is CVE-2020-9818?
CVE-2020-9818 is a critical-severity vulnerability; its CVE record was 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 the CVE record for CVE-2020-9818 published?
The CVE record for CVE-2020-9818 was published on June 9, 2020. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 23, 2025; the record at its source may have been updated since.
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 attention. The CVE record names the fixed release. Apply it.
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 (CRITICAL).
Which products are affected by CVE-2020-9818?
CVE-2020-9818 affects Apple iOS, iPadOS, and watchOS.
How do I remediate CVE-2020-9818?
The CVE record for CVE-2020-9818 names the fix: "This issue is fixed in iOS 13.5 and iPadOS 13.5, iOS 12.4.7, watchOS 6.2.5."

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