CVE-2020-9818

HIGH

8.8

CVSS Score

Published: June 9, 2020 at 04:12 PM UTC

Updated: June 17, 2026 at 03:28 AM UTC

3 products affected across 1 vendoriPhone OSiPadOSwatchOS

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Severity

HIGH8.8

Exploitation

CISA KEV

Exploit prediction

EPSS 2%

SSVC

Active

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score2.3%

EPSS (Exploit Prediction Scoring System) estimates a 2.3% chance this CVE is exploited in the wild within the next 30 days — higher than 84% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

Apple iOS, iPadOS, and watchOS Mail contains an out-of-bounds write vulnerability which may allow memory modification or application termination when processing a maliciously crafted mail message.

Required Action

Apply updates per vendor instructions.

Ransomware Use

Unknown

Added to KEV

Nov 3, 2021

Remediation Due

May 3, 2022

1639 days overdue

Notes

https://nvd.nist.gov/vuln/detail/CVE-2020-9818

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

iPadOS · Apple

95%

v < 13.5

Affected range stops below 13.5, so it looks safe — our inference, not a vendor statement

iPhone OS · Apple

95%

v < 12.4.7v < iOS 12.4.7v < iOS 13.5 and iPadOS 13.513.0 ≤ v < 13.5

Affected range stops below 12.4.7, so it looks safe — our inference, not a vendor statement

Affected range stops below 13.5, so it looks safe — our inference, not a vendor statement

Affected range stops below iOS 12.4.7, so it looks safe — our inference, not a vendor statement

Affected range stops below iOS 13.5 and iPadOS 13.5, so it looks safe — our inference, not a vendor statement

watchOS · Apple

95%

v < 6.2.5v < watchOS 6.2.5

Affected range stops below 6.2.5, so it looks safe — our inference, not a vendor statement

Affected range stops below watchOS 6.2.5, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (4)

x_refsource_MISCRelease NotesVendor Advisory

Source: [email protected]

https://support.apple.com/HT211168

x_refsource_MISCRelease NotesVendor Advisory

Source: [email protected]

https://support.apple.com/HT211169

x_refsource_MISCRelease NotesVendor Advisory

Source: [email protected]

https://support.apple.com/HT211175

US Government Resource

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

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

SSVC — Action Prioritization

SSVCActiveNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.8HIGHCISA-ADP

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: REQUIRED
Scope: UNCHANGED
Confidentiality: HIGH
Integrity: HIGH
Availability: HIGH

Vector?

Quick Info

StatusANALYZED

CWE

CWE-787

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