What is the CVSS score of CVE-2021-1870?

CVE-2021-1870 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 7.9%.

Is CVE-2021-1870 being actively exploited?

Yes, CVE-2021-1870 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, confirming active in-the-wild exploitation. Immediate patching is required.

macOS CVE-2021-1870

CRITICAL

2021-04-02 product-security@apple.com

RCE Apple macOS Fedora Ipados Iphone Os Webkitgtk Mac Os X Fedoraproject

9.8

CVSS 3.1 · NVD

View

Vulnerability Assessment

Impact	CVSS score of 9.8 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.
Exploit ScenarioDerived	This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the critical-severity affected system.

Act Now Prioritize within 24-48h. Why: CRITICAL + in CISA KEV (actively exploited), no patch available.

Exploited in the wild (CISA KEV) No patch listed yet 7.9% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAI

A logic issue was addressed with improved restrictions. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

A logic issue was addressed with improved restrictions. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, iOS 14.4 and iPadOS 14.4. A remote attacker may be able to cause arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited.. Affected products include: Apple Ipados, Apple Iphone Os, Apple Mac Os X, Apple Macos, Webkitgtk.

Know when macOS gets its next vulnerability

Watch products and get an email when something new is published
Check this CVE against your own stack and servers
Exploit and PoC references, threat intelligence from 22 sources

Continue with Google Continue with GitHub

No credit card · 7-day full trial

Severity by source

NVD PRIMARY 9.8 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Added to CISA KEV

Jul 14, 2026 - 04:22 CISA

CVE Published

Apr 02, 2021 - 19:15 nvd

CRITICAL 9.8

DescriptionNVD

Threat Intelligence Overview

EPSS Score

7.9%

Top 6% exploitable

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

CISA KEV

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity CRITICAL

CISA KEV Yes

Public POC No

EPSS 7.9%

Patch available No

Active threat Yes

Deciding rule

CRITICAL + in CISA KEV (actively exploited), no patch available

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Immediate

Exploitation· derived

Active

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact· derived

High

Priority Score

107

Low Medium High Critical

KEV: +50

EPSS: +8

CVSS: +49

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Remote Code Execution CRITICAL

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

Affected Products (CPE)NVD

cpe:2.3:o:apple:ipados:*:*:*:*:*:*:*:*

cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*

cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*

cpe:2.3:o:apple:mac_os_x:10.15.7:-:*:*:*:*:*:*

cpe:2.3:o:apple:mac_os_x:10.15.7:security_update_2020-001:*:*:*:*:*:*

cpe:2.3:o:apple:mac_os_x:10.15.7:supplemental_update:*:*:*:*:*:*

cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*

cpe:2.3:a:webkitgtk:webkitgtk:*:*:*:*:*:*:*:*

cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*

cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*

More in macOS

View all

CVE-2025-34089 CRITICAL Emergency POC

9.3 Jul 03

An unauthenticated remote code execution vulnerability exists in Remote for Mac, a macOS remote control utility develope

CVE-2026-86950 HIGH Act Now POC

8.8 Sep 28

Out-of-bounds write in Apple's iOS, iPadOS, and macOS file-parsing code lets remote attackers achieve arbitrary code exe

CVE-2026-20700 HIGH Act Now POC

7.8 Feb 11

Apple's kernel across all platforms (iOS, macOS, watchOS, visionOS, tvOS) contains a memory corruption vulnerability (CV

CVE-2022-48618 HIGH Act Now

7.0 Jan 09

The issue was addressed with improved checks. Rated high severity (CVSS 7.0). Actively exploited in the wild (cisa kev)

CVE-2024-27822 HIGH Act Now POC

7.8 May 14

A logic issue was addressed with improved restrictions. Rated high severity (CVSS 7.8), this vulnerability is no authent

CVE-2023-22809 HIGH Act Now POC

7.8 Jan 18

In Sudo before 1.9.12p2, the sudoedit (aka -e) feature mishandles extra arguments passed in the user-provided environmen

CVE-2022-46689 HIGH Act Now POC

7.0 Dec 15

A race condition was addressed with additional validation. Rated high severity (CVSS 7.0), this vulnerability is no auth

CVE-2022-32845 CRITICAL Act Now POC

10.0 Sep 23

This issue was addressed with improved checks. Rated critical severity (CVSS 10.0), this vulnerability is remotely explo

CVE-2021-44790 CRITICAL Act Now POC

9.8 Dec 20

A carefully crafted request body can cause a buffer overflow in the mod_lua multipart parser (r:parsebody() called from

CVE-2025-52841 HIGH This Week POC

8.8 Jul 02

Cross-Site Request Forgery (CSRF) vulnerability in Laundry on Linux, MacOS allows to perform an Account Takeover. This i

CVE-2022-3970 HIGH This Week POC

8.8 Nov 13

A vulnerability was found in LibTIFF. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no aut

CVE-2022-0729 HIGH This Week POC

8.8 Feb 23

Use of Out-of-range Pointer Offset in GitHub repository vim/vim prior to 8.2.4440. Rated high severity (CVSS 8.8), this

Same technique RCE

View all

CVE-2021-44228 CRITICAL POC

10.0

CVE-2017-7269 CRITICAL POC

9.8

CVE-2022-47966 CRITICAL POC

9.8

CVE-2012-4681 CRITICAL POC

9.8

CVE-2023-3519 CRITICAL POC

9.8

CVE-2015-5119 CRITICAL POC

9.8

CVE-2016-4117 CRITICAL POC

9.8

CVE-2015-3113 CRITICAL POC

9.8

References

Advisories & patches

ADVISORY https://support.apple.com/en-us/HT212146 ADVISORY https://support.apple.com/en-us/HT212147 REF https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JN6ZOD62CTO54CHTMJTHVEF6R2Y532TJ/ REF https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3L6ZZOU5JS7E3RFYGLP7UFLXCG7TNLU/ REF https://security.gentoo.org/glsa/202104-03 REF https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1870

Search Externally

GitHub PoC

Exploit-DB PacketStorm Snyk Rapid7 Nuclei Templates Trickest PoC

Back