CVE-2021-31010
CVE-2021-31010 is a security flaw in Apple iOS, macOS, watchOS, the operating system on iPhones and iPads. Attackers are using a flaw in Apple iOS, macOS, watchOS. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 25 Aug 2022.[1]
Apple iOS, macOS, watchOS is in things households have, such as phones, computers, browsers and everyday apps, so the fix matters at home as much as at work. Fixed in version 11.6, 2021, 7.6 and 14.8 and others.
Description
CISA calls it a sandbox bypass in Apple iOS, macOS, watchOS. In its words: “In affected versions of Apple iOS, macOS, and watchOS, a sandboxed process may be able to circumvent sandbox restrictions.”[1]
The CVE record adds: “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..”[2]
The underlying weakness is improper input validation (CWE-20), deserialization of untrusted data (CWE-502), in MITRE’s list of common software weaknesses.
It scores 7.5 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record lists these fixed versions: in each line, everything before the version shown is affected.[2]
| Product | Fixed in |
|---|---|
| macOS | 11.6 |
| macOS | 2021 |
| watchOS | 7.6 |
| watchOS | 14.8 |
| watchOS | 12.5 |
Every device with Apple iOS, macOS, watchOS needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 25 Aug 2022, 366 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 15 Sep 2022 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 4%. That’s in the top 11% of the flaws it scores.[4]
CISA assesses it as automatable: attackers can run it against many targets at once.
CISA doesn’t say who was attacked, or how.
Fix
Apple has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Update Apple iOS, macOS, watchOS now.On iPhone and iPad: Settings, General, Software Update. On a Mac: System Settings, General, Software Update. Install it on every Apple device in the house. Then turn on automatic updates, so the next fix arrives on its own.
- Check you’re on 11.6 or later.Fixed in version 11.6, 2021, 7.6 and 14.8 and others. Anything older is what attackers are going after.
- If there’s no update, stop using it.CISA’s advice when a flaw being used in attacks has no fix is to stop using the product until it does.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 7.5.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 4%.[4] |
See also
Other Apple flaws
- CVE-2026-86950, Apple devices: out-of-bounds write ·
- CVE-2026-65400, Apple macOS: improper authentication ·
- CVE-2025-43520, Apple devices: classic buffer overflow ·
- CVE-2025-43510, Apple devices: improper locking ·
- CVE-2025-31277, Apple devices: buffer overflow ·
Other improper input validation flaws
- CVE-2026-93952, Arista VeloCloud Orchestrator: improper input validation ·
- CVE-2019-1068, Microsoft SQL Server: remote code execution ·
- CVE-2026-12569, PTC Windchill and FlexPLM: improper input validation ·
- CVE-2026-34910, Ubiquiti UniFi OS: improper input validation ·
- CVE-2026-6973, Ivanti Endpoint Manager Mobile (EPMM): improper input validation ·
Added the same day
- CVE-2022-26352, dotCMS: unrestricted upload of file ·
- CVE-2022-24706, Apache CouchDB: insecure default initialization of resource ·
- CVE-2022-24112, Apache APISIX: authentication bypass ·
- CVE-2022-22963, VMware Tanzu Spring Cloud: function remote code execution ·
- CVE-2022-2294, WebRTC: heap buffer overflow ·
Every Apple flaw on CISA’s list · Everything added in August 2022
References
- ^ Cybersecurity and Infrastructure Security Agency. “Apple iOS, macOS, watchOS Sandbox Bypass Vulnerability”. Known Exploited Vulnerabilities Catalog, added 25 Aug 2022.
- ^ National Institute of Standards and Technology. “CVE-2021-31010 Detail”. National Vulnerability Database, published 24 Aug 2021.
- ^ Apple. Advisories and fixes: support.apple.com, support.apple.com, support.apple.com, support.apple.com, support.apple.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.037, percentile 89.7, 31 Oct 2026.
- CVE Program. “CVE-2021-31010”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.