SecPod

Learn Search

Search across all Learn content

← Back to Security Research
Apple Critical Security Updates April 2021

Apple Critical Security Updates April 2021

Apple released security updates for multiple products. The exploitation of some of these security flaws will allow an attacker to bypass many core Apple security mechanisms, crash the application, potentially control affected systems, and putting Mac users at great risk. A vulnerability management s...

Apr 27, 2021By Rinu K4 min read

Apple released security updates for multiple products. The exploitation of some of these security flaws will allow an attacker to bypass many core Apple security mechanisms, crash the application, potentially control affected systems, and putting Mac users at great risk. A vulnerability management solution will help in mitigating this.

The updates for macOS include fixes for 64 vulnerabilities. Auto patching can fix all off these vulnerabilities. These flaws allow attackers to execute arbitrary code with kernel or system privileges, bypass privacy preferences, read restricted memory, cause unexpected application termination or heap corruption, disclose sensitive information, read arbitrary files, conduct cross-site scripting and phishing attacks, etc.

Zero-Day  (CVE-2021-30657)

A critical zero-day vulnerability exploited in the wild by Shlayer malware is fixed in this April’s security update. The vulnerability allows an attacker to bypass core Apple security mechanisms such as Apple’s File Quarantine, Gatekeeper, and Notarization security checks. It also runs second-stage malicious payloads. The vulnerability is discovered and reported by Security researcher Cedric Owens.

Zero-Day  (CVE-2021-30661)

Another critical zero-day vulnerability related to WebKit Storage is also being exploited in the wild.  It impacts iOS and watchOS devices. The vulnerability allows an attacker to conduct remote code execution.

Apple Security Updates Summary for April 2021

macOS

iOS and iPadOS

Xcode

  • Affected OS: macOS Big Sur
  • Affected features: Git
  • Impact: Arbitrary Code Execution
  • CVEs: CVE-2021-21300

iCloud

  • Affected OS: macOS Catalina and Mojave
  • Affected features: WebRTC, WebKit
  • Impact: Cross-Site Scripting, Memory Corruption
  • CVEs: CVE-2021-1825, CVE-2020-7463

SanerNow detects these vulnerabilities and automatically fixes them by applying security updates. Use SanerNow to keep your systems updated and secure.

Featured Posts

Open CVE-2023-49105: The ownCloud Authentication Flaw That Exposed Sensitive Credentials
CVE-2023-49105: The ownCloud Authentication Flaw That Exposed Sensitive Credentials

CVE Research

CVE-2023-49105: The ownCloud Authentication Flaw That Exposed Sensitive Credentials

Sep 25, 2026

Open Patch Analysis & Exploitation Timeline: RouterOS SSH Attacks Predate Production Fixes in CISA's September 10, 2026 KEV Additions
Patch Analysis & Exploitation Timeline: RouterOS SSH Attacks Predate Production Fixes in CISA's September 10, 2026 KEV Additions

CVE Research

Patch Analysis & Exploitation Timeline: RouterOS SSH Attacks Predate Production Fixes in CISA's September 10, 2026 KEV Additions

Two MikroTik RouterOS CVEs entered CISA KEV seven days after production fixes. Dated reporting places SSH-chain exploitation involving CVE-2026-86060 at least one calendar day before those releases; no comparable start date is established for CVE-2026-67277.

Sep 25, 2026

Open Patch Analysis & Exploitation Timeline: A Day-Old Chrome Bug and an Eight-Month-Old Fortinet Flaw Share the Same KEV Batch
Patch Analysis & Exploitation Timeline: A Day-Old Chrome Bug and an Eight-Month-Old Fortinet Flaw Share the Same KEV Batch

CVE Research

Patch Analysis & Exploitation Timeline: A Day-Old Chrome Bug and an Eight-Month-Old Fortinet Flaw Share the Same KEV Batch

Four vulnerabilities added to CISA’s KEV catalog on September 9, 2026 show widely different timelines between public disclosure and formal exploitation-based prioritization, ranging from one day to 239 days.

Sep 24, 2026

Open TA412/APT31: Mapping Threat Actor Patterns to CVE Exploitation Chains

TA412/APT31: Mapping Threat Actor Patterns to CVE Exploitation Chains

CVE Research

TA412/APT31: Mapping Threat Actor Patterns to CVE Exploitation Chains

A chronological look at how a long-running China-nexus espionage cluster evolved from server-side exploitation to a chained Chrome/Windows zero-day kit — and what that shift signals.

Sep 24, 2026