CVE-2021-1879 : This issue was addressed by improved management of object lifetimes. This issue

This issue was addressed by improved management of object lifetimes. This issue is fixed in iOS 12.5.2, iOS 14.4.2 and iPadOS 14.4.2, watchOS 7.3.3. Processing maliciously crafted web content may lead to universal cross site scripting. Apple is aware of a report that this issue may have been actively exploited..

Published 2021-04-02 19:15:21

Updated 2025-02-28 14:44:49

Source Apple Inc.

View at NVD, CVE.org

Vulnerability category: Cross site scripting (XSS)

Products affected by CVE-2021-1879

Apple » Iphone Os
Versions from including (>=) 13.0 and before (<) 14.4.2
cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
Matching versions
Apple » Iphone Os
Versions before (<) 12.5.2
cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
Matching versions
Apple » Watchos
Versions before (<) 7.3.3
cpe:2.3:o:apple:watchos:*:*:*:*:*:*:*:*
Matching versions
Apple » Ipados
Versions before (<) 14.4.2
cpe:2.3:o:apple:ipados:*:*:*:*:*:*:*:*
Matching versions

CVE-2021-1879 is in the CISA Known Exploited Vulnerabilities Catalog

CISA vulnerability name:

Apple iOS, iPadOS, and watchOS WebKit Cross-Site Scripting (XSS) Vulnerability

CISA required action:

Apply updates per vendor instructions.

CISA description:

Apple iOS, iPadOS, and watchOS WebKit contain an unspecified vulnerability that allows for universal cross-site scripting (XSS) when processing maliciously crafted web content. This vulnerability could impact HTML parsers that use WebKit, including but not limited to Apple Safari and non-Apple produ

Notes:

https://nvd.nist.gov/vuln/detail/CVE-2021-1879

Added on 2021-11-03 Action due date 2021-11-17

Exploit prediction scoring system (EPSS) score for CVE-2021-1879

EPSS FAQ

2.05%

Probability of exploitation activity in the next 30 days EPSS Score History

~ 82 %

Percentile, the proportion of vulnerabilities that are scored at or less

CVSS scores for CVE-2021-1879

Base Score	Base Severity	CVSS Vector	Exploitability Score	Impact Score	Score Source	First Seen
4.3	MEDIUM	AV:N/AC:M/Au:N/C:N/I:P/A:N	8.6	2.9	NIST
Access Vector: Network Access Complexity: Medium Authentication: None Confidentiality Impact: None Integrity Impact: Partial Availability Impact: None
6.1	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N	2.8	2.7	134c704f-9b21-4f2e-91b3-4a467353bcc0	2025-01-29
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: Required Scope: Changed Confidentiality: Low Integrity: Low Availability: None
6.1	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N	2.8	2.7	NIST
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: Required Scope: Changed Confidentiality: Low Integrity: Low Availability: None

CWE ids for CVE-2021-1879

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Assigned by:
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)
- nvd@nist.gov (Primary)

References for CVE-2021-1879

https://support.apple.com/en-us/HT212257

About the security content of iOS 12.5.2 - Apple Support
Vendor Advisory;Release Notes
https://support.apple.com/en-us/HT212258

About the security content of watchOS 7.3.3 - Apple Support
Vendor Advisory;Release Notes
https://support.apple.com/en-us/HT212256

About the security content of iOS 14.4.2 and iPadOS 14.4.2 - Apple Support
Vendor Advisory;Release Notes