CVE-2020-9818: Apple iOS, iPadOS, and watchOS Out-of-Bounds Write Vulnerability
Vulnerability summary
CVE-2020-9818 is a high (CVSS 8.8) Out-of-bounds Write vulnerability in Apple iOS, iPadOS, and watchOS. It is known to be exploited: CISA lists it, first on 03-11-2021. EPSS estimates a 2.29% chance of exploitation in the next 30 days, higher than 82.9% of scored vulnerabilities.
Timeline
- 09-06-2020PublishedVulnerability first disclosed.
- 03-11-2021Added to CISA KEVApple iOS, iPadOS, and watchOS Out-of-Bounds Write Vulnerability
- 03-05-2022CISA remediation dueApply updates per vendor instructions.
- 20-12-2025Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 2 sources · 2 versions- NVDNIST8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS trend
Probability
2.29%
Chance of exploitation in the next 30 days
Percentile
83%
Versus all other CVEs
30-day change
0.00 pp
From 2.29% on 20-09-2026
Known exploited
Compare KEV catalogs
CISA KEVListed- Added
- 03-11-2021
- Federal due date
- 03-05-2022
CISA required action
Apply updates per vendor instructions. nvd.nist.gov/vuln/detail/CVE-2020-9818
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
1 vendor · 5 products
References
4 links- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-9818Government ResourceUS Government Resource