CVE-2020-9818
HighExploitedPublic exploitAn out-of-bounds write issue was addressed with improved bounds checking.
Published Jun 9, 2020 · Updated Dec 20, 2025
Key Facts
Patch immediately- CVE-2020-9818 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting Ipados (Apple), Iphone OS (Apple), watchOS (Apple) and 2 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Apr 22, 2020. Public exploit code is available.
- EPSS estimates a 2.3% probability of exploitation in the next 30 days.
- Fixed versions are available, including Ipados 13.5, Iphone OS 12.4.7, watchOS 6.2.5.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
8.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
2.3%
Higher than 82.8% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2020-9818 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Nov 3, 2021 | May 3, 2022 | Not reported |
| Industry KEV feed | Apr 22, 2020 | May 3, 2022 | Not reported |
| CIRCL KEV | Nov 3, 2021 | May 3, 2022 | Not reported |
| ENISA EUVD | Nov 3, 2021 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
6 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| IpadosApple | See advisory | 13.5 |
| Iphone OSApple | See advisory | 12.4.7 |
| watchOSApple | >= unspecified | 6.2.5 |
| iOS | >= unspecified | iOS 13.5 and iPadOS 13.5 |
| iOS-1 | >= unspecified | iOS 12.4.7 |
Patched Releases
Ipados
13.5
Iphone OS
12.4.7
watchOS
6.2.5, watchOS 6.2.5
iOS
iOS 13.5 and iPadOS 13.5
iOS-1
iOS 12.4.7
Timeline
Added to Industry KEV feed
Apr 22, 2020
Publicly disclosed
Jun 9, 2020
Added to CISA KEV
Nov 3, 2021
Added to CIRCL KEV
Nov 3, 2021
Added to ENISA EUVD
Nov 3, 2021
Last updated
Dec 20, 2025
Weakness Type
- CWE-787 Out-of-bounds Write
References
- advisoryhttps://support.apple.com/HT211168
- advisoryhttps://support.apple.com/HT211169
- advisoryhttps://support.apple.com/HT211175
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
FAQ
Common Questions.
An out-of-bounds write issue was addressed with improved bounds checking.
Affected: Ipados (Apple); Iphone OS (Apple); watchOS (Apple) versions >= unspecified, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Apr 22, 2020.
Yes. It was added on Nov 3, 2021 with a federal remediation due date of May 3, 2022.
Public exploit code is available.
Fixed versions are available, including Ipados 13.5, Iphone OS 12.4.7, watchOS 6.2.5.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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