Security readout for executives and security teams
Plain-English summary
A maliciously crafted email message could cause memory corruption on affected Apple mobile and watch devices. Apple fixed it through improved memory handling in listed iOS, iPadOS, and watchOS releases. Although CVSS is medium, CISA KEV listing makes this operationally urgent for any legacy or unmanaged Apple fleet.
Executive priority
Handle as a high-priority hygiene and legacy-device remediation item. The technical severity is medium, but known exploitation means delayed patching creates unnecessary business risk, especially where executives or high-value users rely on Apple Mail-enabled devices.
Technical view
CVE-2020-9819 is a mail message processing flaw described as memory consumption leading to heap corruption. The CVSS 3.1 vector is network, low complexity, no privileges, user interaction required, unchanged scope, and low availability impact. Apple lists fixes in iOS/iPadOS 13.5, iOS 12.4.7, watchOS 6.2.5, and watchOS 5.3.7.
Likely exposure
Exposure is most likely on iPhone, iPad, and Apple Watch devices running versions older than the fixed releases and capable of processing malicious mail messages. The source bundle does not identify exact device models, vulnerable build ranges, or enterprise configuration prerequisites.
Exploitation context
CISA KEV inclusion supports known exploitation. The provided sources do not describe campaign scope, exploit reliability, attacker groups, or technical exploitation details. Treat this as a confirmed exploited Apple ecosystem issue without assuming current broad exploitation beyond the KEV signal.
Researcher notes
The evidence identifies mail-message-triggered heap corruption but does not provide root-cause internals, vulnerable code paths, affected model lists, or exploit mechanics. Validation should focus on Apple security update coverage, fleet version evidence, and KEV-driven remediation tracking rather than exploit reproduction.
Mitigation direction
- Update iOS and iPadOS devices to Apple-fixed releases or later.
- Update watchOS devices to Apple-fixed releases or later.
- Prioritize unmanaged, BYOD, executive, and mail-enabled legacy devices.
- Check Apple guidance for any model-specific update constraints.
- Retire devices that cannot receive supported fixed versions.
Validation and detection
- Inventory iOS, iPadOS, and watchOS versions across managed and BYOD fleets.
- Confirm devices meet or exceed iOS/iPadOS 13.5 or iOS 12.4.7 where applicable.
- Confirm Apple Watch devices meet or exceed watchOS 6.2.5 or 5.3.7 where applicable.
- Review MDM compliance reports for stale, offline, or unmanaged devices.
- Track CISA KEV remediation status for affected assets.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-787: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-9819 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4.3 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L2.81.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://support.apple.com/HT211168CVE reference · x_refsource_MISC
- https://support.apple.com/HT211175CVE reference · x_refsource_MISC
- https://support.apple.com/HT211169CVE reference · x_refsource_MISC
- https://support.apple.com/HT211176CVE reference · x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-9819CVE reference · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.