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CVE-2021-30661 Apple CVE debrief

CVE-2021-30661 is an Apple WebKit Storage use-after-free vulnerability that CISA added to its Known Exploited Vulnerabilities catalog. That KEV listing means the issue is considered known to be exploited in the wild, so defenders should treat Apple patching as urgent and verify that vendor updates have been applied across managed devices.

Vendor
Apple
Product
Multiple Products
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2021-11-03
Original CVE updated
2021-11-03
Advisory published
2021-11-03
Advisory updated
2021-11-03

Who should care

IT, endpoint security, and vulnerability management teams responsible for Apple devices and any Apple software that depends on WebKit should prioritize this CVE. It is especially important for organizations with large fleets, delayed patch windows, or limited device visibility.

Technical summary

The supplied official records identify this issue as a WebKit Storage use-after-free vulnerability affecting Apple multiple products. A use-after-free condition is a memory-safety flaw that can lead to unstable behavior and, depending on the affected code path and execution context, may be exploitable. The CISA KEV entry confirms it is a known exploited vulnerability, but the supplied corpus does not include additional technical specifics such as affected versions or exploit mechanics.

Defensive priority

High. CISA placed CVE-2021-30661 in the KEV catalog on 2021-11-03 with a remediation due date of 2021-11-17, indicating an urgent patch-management priority.

Recommended defensive actions

  • Apply Apple updates according to vendor instructions as soon as possible.
  • Confirm which Apple devices and software versions are exposed, then validate that remediation reached every managed endpoint.
  • Escalate or shorten normal patch SLAs for any systems that cannot yet be updated.
  • Review security telemetry for unusual crashes or instability in WebKit-based components as part of post-patch monitoring.
  • Track KEV status and close the finding only after patch verification is complete.

Evidence notes

This debrief is based only on the supplied CISA KEV metadata and the official CVE/NVD/CISA links provided in the corpus. The source data identifies the issue as an Apple WebKit Storage use-after-free vulnerability and confirms KEV listing on 2021-11-03. No additional vendor advisory details, affected version ranges, or exploit particulars were supplied, so those specifics are intentionally not included.

Official resources

Public, defensive-only debrief derived from official CVE and CISA KEV sources. No exploit code, weaponized reproduction, or unsupported claims are included.