Security readout for executives and security teams
CVE-2021-30858 is a memory safety flaw in Apple web content handling. A malicious webpage could trigger arbitrary code execution. Apple reported possible active exploitation, and CISA lists it in KEV, so exposed Apple devices and referenced WebKit-based components should be treated as urgent legacy patch gaps. Most exposure is on unpatched Apple endpoints running affected iOS, iPadOS, macOS Big Sur, or Safari versions named by Apple advisories. Public references also include WebKitGTK, WPE WebKit, Fedora, and Debian advisories, so Linux WebKit packages should be checked against vendor guidance. Treat this as an urgent remediation item for legacy Apple and WebKit exposure. The vulnerability enables code execution through web content and has credible exploitation evidence, making patch verification more important than routine vulnerability backlog handling. Mitigation focus: Update iOS and iPadOS to vendor-fixed releases named by Apple.; Update macOS Big Sur to 11.6 or later vendor-fixed guidance.; Update Safari where Apple identifies Safari 14.1.2 as fixed..
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CWE-416: Exact CWE lookup
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Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-30858 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 8.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://support.apple.com/en-us/HT212804CVE reference · x_refsource_MISC
- https://support.apple.com/en-us/HT212807CVE reference · x_refsource_MISC
- FEDORA-2021-c00e45b6c0CVE reference · vendor-advisory, x_refsource_FEDORA
- DSA-4975CVE reference · vendor-advisory, x_refsource_DEBIAN
- DSA-4976CVE reference · vendor-advisory, x_refsource_DEBIAN
- https://support.apple.com/kb/HT212824CVE reference · x_refsource_CONFIRM
- FEDORA-2021-edf6957b7dCVE reference · vendor-advisory, x_refsource_FEDORA
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30858CVE reference · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.