Threats / Apple / CVE-2020-9818
CVE-2020-9818
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Apple iOS, iPadOS, and watchOS vulnerability
Apple iOS, iPadOS, and watchOS Mail contains an out-of-bounds write vulnerability in mail message processing that may enable memory modification or application termination.
Verdict
Today item — known-exploited.
An out-of-bounds write in Mail allows attackers to craft malicious messages that corrupt memory or crash the application. The vulnerability has been exploited in the wild, though no ransomware campaigns are attributed to it.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
2 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03).
Probability (EPSS)
EPSS 0.02286 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Apple, iOS, iPadOS, and watchOS. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-787 Out-of-bounds Write — weakness family: Memory safety.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious email message with specially formatted content designed to trigger an out-of-bounds write when processed by the Mail application.
Business
Users receive unsolicited malicious email that exploits their device without additional user interaction beyond message delivery.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I send the crafted message to target users, relying on Mail to automatically process and parse the message content.
Business
Attack surface includes all users with Mail enabled across iOS, iPadOS, and watchOS devices in the affected versions.
3
Lateral reach — past segmentation narrative 3
Attacker
I trigger memory corruption through the out-of-bounds write, potentially modifying adjacent memory regions or causing a denial of service.
Business
Device stability is compromised, with Mail application crashes disrupting user productivity and potentially affecting system reliability.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05