Vulnerability report

Trusted Third Party Report Confirmed Confidence In CISA KEV

CVE-2021-31010

macOS Deserialization

Apple / macOS · affected before 11.6

Watch CVE-2021-31010 Browse KEV feed
Severity
CVSS 7.5 · High
Confidence
Confirmed
Exploit status
Trusted Third Party Report
EPSS
3.4%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-31010 is an unauthenticated vulnerability affecting Apple macOS, watchOS. A deserialization issue was addressed through improved validation.

Have exploitation attempts been observed?

Yes. Exploitation attempts have been reported for this vulnerability. Previdian lists it as a known exploited vulnerability. Listed in CISA KEV. Confidence is confirmed.

Who is affected?

Apple / macOS and watchOS, including affected before 11.6, affected before 2021, and affected before 7.6.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

A deserialization issue was addressed through improved validation

A deserialization issue was addressed through improved validation. This issue is fixed in Security Update 2021-005 Catalina, iOS 12.5.5, iOS 14.8 and iPadOS 14.8, macOS Big Sur 11.6, watchOS 7.6.2.

A sandboxed process may be able to circumvent sandbox restrictions. Apple was aware of a report that this issue may have been actively exploited at the time of release..

Apple Affected
macOS
Before 11.6 Before 2021
Apple Affected
watchOS
Before 7.6 Before 14.8 Before 12.5
Published
24 Aug 2021
Exploitation Attempts Reported
25 Aug 2022
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

ios macos nessus_scanner cisa

CVE References

Exploitation evidence

Evidence of exploitation attempts

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploitation Attempts Observed in the Wild

CISA

Recorded 25 Aug 2022

A trusted third party reported exploitation attempts.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CISA First 2022-08-25 00:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nessus https://www.tenable.com/plugins/nessus/153652 02 Jun 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

7.5 High

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS

3.4%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Deserialization of Untrusted Data CWE-502

All CVSS Scores

CVSS v3.1 7.5 High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS v2.0 5.0 Medium

AV:N/AC:L/Au:N/C:N/I:P/A:N

Timeline

From disclosure to observed exploitation attempts

  1. 09:27 UTC

    Nessus plugin available

    Scanner coverage available

  2. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  3. 18:51 UTC

    CVE published

    Vulnerability disclosed publicly

  4. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

Start 14-day Pro trial Read API docs
  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2021-31010

Sample API response 
{
  "cve_id": "CVE-2021-31010",
  "confidence": "Confirmed",
  "cvss_score": 7.5,
  "cvss_estimated": false,
  "epss_score": 0.03369,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}