CVE-2020-9819Known exploitationNetwork attack vector

Heap corruption via crafted mail message processing

Published Jun 9, 2020 · Updated Dec 20, 2025

Memory corruption in Mail in Apple iOS and watchOS allows remote attackers to corrupt heap memory by sending a malicious mail message. Apple identifies incorrect memory consumption during Mail processing but does not disclose the faulty function or exact memory operation. Delivery of a crafted message and user interaction are required, and the published assessment limits the consequence to a service interrupt.

CVSS severity4.3
Medium
EPSS probability2.18%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Memory corruption in Mail in Apple iOS and watchOS allows remote attackers to corrupt heap memory by sending a malicious mail message. Apple identifies incorrect memory consumption during Mail processing but does not disclose the faulty function or exact memory operation. Delivery of a crafted message and user interaction are required, and the published assessment limits the consequence to a service interrupt.

The record

CVE
CVE-2020-9819
Published
Jun 9, 2020
Updated
Dec 20, 2025
Vendor
Apple
Product
iOS
Classifications
CWE-787
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 9, 2020CVE publishedPublication date reported by the CVE source.
  2. Dec 20, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <iOS 12.4.7
  2. Affected versionversion=unspecified <iOS 13.5 and iPadOS 13.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Apple · iOSversion=unspecified <iOS 12.4.7; version=unspecified <iOS 13.5 and iPadOS 13.5
Apple · watchOSversion=unspecified <watchOS 5.3.7; version=unspecified <watchOS 6.2.5

Published CVSS scores

4.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
4.3NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
4.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo