---
id: "CVE-2021-31010"
kind: "vulnerability"
aliases: ["CVE-2021-31010"]
title: "A deserialization issue was addressed through improved validation"
severity: "high"
cvss: 7.5
epss: 0.03673
exploited: true
status: "open"
category: "vendor"
products: [{"name": "Apple iOS, macOS, watchOS", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "apple ipados", "fixed": ["14.8"], "affected": "< 14.8", "ecosystem": "vendor"}, {"name": "apple iphone os", "fixed": ["12.5.5"], "affected": ">= 12.0, < 12.5.5", "ecosystem": "vendor"}, {"name": "apple iphone os", "fixed": ["14.8"], "affected": ">= 14.0, < 14.8", "ecosystem": "vendor"}, {"name": "apple mac os x", "fixed": ["10.15.7"], "affected": ">= 10.15, < 10.15.7", "ecosystem": "vendor"}, {"name": "apple mac os x", "fixed": [], "affected": "= 10.15.7", "ecosystem": "vendor"}, {"name": "apple macos", "fixed": ["11.6"], "affected": ">= 11.0, < 11.6", "ecosystem": "vendor"}, {"name": "apple watchos", "fixed": ["7.6.2"], "affected": "< 7.6.2", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["apple-devices", "exploited", "ios", "macos", "vendor", "watchos"]
not_affected_if: ["unknown"]
published_at: "2021-08-24T19:15:24+00:00"
first_seen_at: "2026-10-23T19:11:52+00:00"
updated_at: "2026-10-23T22:29:04+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-31010", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2021-31010", "first_seen_at": "2026-10-23T19:13:45+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-31010", "first_seen_at": "2026-10-23T22:29:04+00:00"}]
---

# A deserialization issue was addressed through improved validation

A sandbox escape in Apple iOS, macOS and watchOS lets a process confined by the sandbox break out of its restrictions. It is listed as actively exploited in the wild per CISA's KEV catalog.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Apple iOS, macOS, watchOS affected ? fixed ?
- vendor:apple ipados affected < 14.8 fixed 14.8
- vendor:apple iphone os affected >= 12.0, < 12.5.5 fixed 12.5.5
- vendor:apple iphone os affected >= 14.0, < 14.8 fixed 14.8
- vendor:apple mac os x affected >= 10.15, < 10.15.7 fixed 10.15.7
- vendor:apple mac os x affected = 10.15.7 fixed ?
- vendor:apple macos affected >= 11.0, < 11.6 fixed 11.6
- vendor:apple watchos affected < 7.6.2 fixed 7.6.2

## How to check

Check the installed OS version under Settings > General > About (iOS and watchOS) or Apple menu > About This Mac (macOS) and compare it with Apple's security notes for this CVE. Sources do not give the fixed versions.

## Fix

Apply the Apple update that addresses CVE-2021-31010 per vendor instructions, as CISA requires. Fixed version numbers: unknown in the sources.

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-31010
- 2026-10-23T19:13:45+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2021-31010
- 2026-10-23T22:29:04+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2021-31010

## From the sources

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..

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_