Is CVE-2021-1879 actively exploited?

Yes. KEV Intelligence tracks CVE-2021-1879 as a known exploited vulnerability. Confidence is confirmed.

What exploitation activity has KEV Intelligence observed?

KEV Intelligence has not yet recorded sensor-observed exploitation attempts for CVE-2021-1879. Our sensors continue to monitor for activity targeting this CVE.

Which versions are affected?

CVE-2021-1879 affects Apple iOS and iPadOS and 2 other products. Reported affected versions include unspecified to < 14.4, unspecified to < 12.5, and unspecified to < 7.3.

Yes. CVE-2021-1879 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2021-1879

Q: How should organizations remediate it?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Q: Is it in CISA KEV?

Yes. CVE-2021-1879 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

iOS and iPadOS Cross-Site Scripting

Apple / iOS and iPadOS · affected before 14.4

View live feed Monitor via API

Severity: CVSS 6.1 · Medium
Confidence: Confirmed
Exploit status: Exploited in the wild
EPSS: 6.8%
First observed: —
Last observed: —

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-1879 is an unauthenticated vulnerability affecting Apple iOS and iPadOS and 2 other products. This issue was addressed by improved management of object lifetimes. This issue is fixed in iOS 12.5.2, iOS 14.4.2...

Is it exploited?

Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.

Who is affected?

Apple / iOS and iPadOS affected before 14.4.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

This issue was addressed by improved management of object lifetimes

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..

Vendor Product Affected Status

Apple iOS and iPadOS Before 14.4 Affected

Apple iOS Before 12.5 Affected

Apple watchOS Before 7.3 Affected

Published: 02 Apr 2021
Exploitation Reported: 03 Nov 2021
Attack vector: Remote
Complexity: Low
Privileges: None
User interaction: Required

CVE References

CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2021-1879
support.apple.com/en-us/HT212256 support.apple.com · CVE Record https://support.apple.com/en-us/HT212256
support.apple.com/en-us/HT212257 support.apple.com · CVE Record https://support.apple.com/en-us/HT212257
support.apple.com/en-us/HT212258 support.apple.com · CVE Record https://support.apple.com/en-us/HT212258

Exploitation evidence

Why KEV Intelligence marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 03 Nov 2021

Independent exploitation attestation added to the KEV Intelligence record.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.

Learn about Pro API access

Source	Added
CISA First	2021-11-03 00:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets: 0
User-Agents: 0

Raw values available in Pro and Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

6.1 Medium

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS

6.8%

Weaknesses

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

All CVSS Scores

CVSS v3.1 6.1 Medium

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS v2.0 4.3 Medium

AV:N/AC:M/Au:N/C:N/I:P/A:N

Timeline

From disclosure to observed exploitation

03 Nov 2021
Added to CISA KEV

Listed in the CISA Known Exploited Vulnerabilities catalog
02 Apr 2021
CVE published

Vulnerability disclosed publicly
08 Dec 2020
CVE ID reserved

Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

View Pro pricing Read API docs

Evidence confidence and provenance
First-party sensor telemetry
PoC and scanner references
Affected versions and enrichment
Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2021-1879

Free JSON includes basic KEV fields

{
  "cve_id": "CVE-2021-1879",
  "confidence": "Confirmed",
  "cvss_score": 6.1,
  "cvss_estimated": false,
  "epss_score": 0.06845,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}

Early warning alerts

Get alerts on high-impact exploitation

Receive curator-selected alerts when exploitation activity warrants attention. Each alert includes the evidence and context needed to decide what requires attention now.