CVE-2021-1747
An out-of-bounds write was addressed with improved input validation.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.90%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
An out-of-bounds write was addressed with improved input validation. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, watchOS 7.3, tvOS 14.4, iOS 14.4 and iPadOS 14.4. Processing maliciously crafted web content may lead to code execution.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- EPSS
- 0.90% probability · 59th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-787
- Affected
- apple/ipados · apple/iphone os · apple/mac os x · apple/macos · apple/tvos · apple/watchos
- Source
- product-security@apple.com
EPSS 0.9% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://support.apple.com/en-us/HT212146Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212147Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212148Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212149Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212146Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212147Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212148Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212149Release Notes, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.