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PatchSiren cyber security CVE debrief

CVE-2020-9859 Apple CVE debrief

CVE-2020-9859 is an Apple Multiple Products code execution vulnerability that CISA added to the Known Exploited Vulnerabilities catalog on 2021-11-03. Because it appears in KEV, defenders should treat it as a high-priority issue and apply Apple’s update guidance without delay across relevant environments.

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

Organizations that manage Apple products or services should care, especially security teams responsible for endpoint fleets, privileged users, and externally reachable systems. Any environment that depends on Apple software should prioritize this CVE because CISA has flagged it as known exploited.

Technical summary

The supplied corpus identifies this issue only as a code execution vulnerability affecting Apple Multiple Products. The KEV listing confirms it is considered known exploited, but the corpus does not provide affected versions, attack vector details, or exploitation mechanics. The most reliable defensive interpretation from the supplied sources is that this vulnerability warrants prompt remediation using vendor instructions.

Defensive priority

High. CISA’s KEV placement indicates this is a known-exploited vulnerability, which makes timely patching more urgent than routine maintenance. The supplied due date in KEV is 2022-05-03, underscoring the need for rapid remediation in exposed or business-critical Apple environments.

Recommended defensive actions

  • Apply Apple updates and remediation guidance as directed by the vendor.
  • Inventory Apple products in the environment so affected assets can be identified quickly.
  • Prioritize internet-facing, high-value, and user-facing Apple systems for verification and remediation.
  • Validate that patching completed successfully and track any systems that remain outstanding.
  • Monitor official Apple and CISA advisories for any additional guidance or clarification.

Evidence notes

This debrief is limited to the supplied CISA KEV record and official links. The corpus confirms the CVE, vendor, product family, vulnerability class, KEV date added, and due date. It does not include version ranges, root cause details, exploit chain details, or mitigation steps beyond applying vendor updates.

Official resources

Public defensive summary based on CISA KEV data and official records only. No exploit details, reproduction steps, or unsupported technical claims included.