CVE-2021-1879
Apple iOS, iPadOS, and watchOS WebKit Cross-Site Scripting (XSS) Vulnerability
- Medium 6.1
- Exploited: added to CISA KEV 3 Nov 2021
Description
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..
Key facts
- Published
- 2 Apr 2021
- Last changed
- 21 Oct 2025
- Assigned by
- apple
- KEV added
- 3 Nov 2021
- KEV fix due
- 17 Nov 2021
- EPSS
- 7.082% likely to be exploited in the next 30 days, higher than 94.32% of CVEs (scores for 15 Nov 2026)
- SSVC (CISA)
- Exploitation: active; Automatable: no; Technical impact: partial
Severity scores
Each score is shown as its source gave it. They are not averaged or merged.
- 6.1CVSS 3.1, Mediumfrom CISA (ADP container)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
What to do
- Apply updates per vendor instructions.CISA KEV required action
Historical context and remediation
This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.
No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.
Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| Apple | iOS and iPadOS |
|
| Apple | iOS |
|
| Apple | watchOS |
|
Timeline
- 2 Apr 2021 Published
- 3 Nov 2021 CVE-2021-1879 added to CISA KEV
- 3 Nov 2021 Added to the CISA KEV catalogue
Weakness
Practice this bug class
HackZoneLabs has a hands-on lab on XSS (stored, reflected, DOM) (CWE-79).