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Vulnerabilities

Vulnerability · CVE-2021-30858

Apple iOS, iPadOS, macOS Use-After-Free Vulnerability

Published Aug 24, 2021 · catalog updated Jun 16, 2026 · Apple iOS, iPadOS, and macOS

Patch now

CVE-2021-30858 is in the CISA known-exploited catalog, due Nov 17, 2021. Confirm Apple iOS, iPadOS, and macOS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
High8.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
13.38%
Remediation
Remediation guidance
Affected products
cpe apple/ipados · cpe apple/iphone os · cpe apple/macos · cpe debian/debian linux · cpe fedoraproject/fedora · vendor Apple iOS, iPadOS, and macOS

Apple iOS, iPadOS, and macOS WebKit contain a use-after-free vulnerability that leads to code execution 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 products which rely on WebKit for HTML processing.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe apple/ipadosversion unspecified
  • cpe apple/iphone osversion unspecified
  • cpe apple/macosversion unspecified
  • cpe debian/debian linux10.0
  • cpe debian/debian linux11.0
  • cpe fedoraproject/fedora33
  • cpe fedoraproject/fedora34
  • vendor Apple iOS, iPadOS, and macOSversion unspecified

How to fix CVE-2021-30858

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-30858 is in the CISA known-exploited catalog, due Nov 17, 2021. Confirm Apple iOS, iPadOS, and macOS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with debian/debian linux 10.0; debian/debian linux 11.0. Apply updates per vendor instructions.

What should an analyst verify?

CWE-416: Use After Free. EPSS 13.38%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 24, 2021 · Catalog

    Detected

    Apple iOS, iPadOS, and macOS WebKit contain a use-after-free vulnerability that leads to code execution 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 products which rely on WebKit for HTML processing.

  2. Nov 3, 2021 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Nov 17, 2021 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    Apple iOS, iPadOS, and macOS WebKit contain a use-after-free vulnerability that leads to code execution 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 products which rely on WebKit for HTML processing.

Sources

  • CISA KEVConfirmed exploitationCVE-2021-30858

    Apple iOS, iPadOS, and macOS WebKit contain a use-after-free vulnerability that leads to code execution 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 products which rely on WebKit for HTML processing.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2021-30858

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-30858

    30-day exploitation probability 13.4%

    first.org
  • NIST NVDVulnerability recordCVE-2021-30858

    A use after free issue was addressed with improved memory management. This issue is fixed in iOS 14.8 and iPadOS 14.8, macOS Big Sur 11.6. Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been act

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2021-30858

    Apple iOS, iPadOS, and macOS WebKit contain a use-after-free vulnerability that leads to code execution 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 products

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.