How severe is CVE-2021-30900?

CVE-2021-30900 has a CVSS score of 7.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-30900?

Affected package information for CVE-2021-30900 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2021-30900?

No fixed version has been published for CVE-2021-30900 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2021-30900 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2021-30900, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-30900?

CVE-2021-30900 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 66th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

Is CVE-2021-30900 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2021-30900 (Apple iOS, iPadOS, and macOS Out-of-Bounds Write Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2023-03-30. CISA required all US federal civilian agencies to remediate this vulnerability by 2023-04-20. The required action was: Apply updates per vendor instructions. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2021-30900?

CVE-2021-30900 is classified as Out-of-bounds Write (CWE-787). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Which products and versions are affected by CVE-2021-30900?

CVE-2021-30900 affects apple ipados (1 version, e.g. 15.0); apple iphone os (1 version, e.g. 15.0); apple macos. Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2021-30900 published, and has it been updated?

CVE-2021-30900 was published on August 24, 2021 and was last updated on October 23, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2023-03-30 — agencies required to remediate by 2023-04-20

CVE-2021-30900

HIGH

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 14.8.1 and iPadOS 14.8.1, iOS 15.1 and iPadOS 15.1. A malicious application may…

Published

Aug 24, 2021

Updated

Oct 23, 2025

Affected

0 pkgs

Patched

None yet

Exploits

1 known

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk66th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 14.8.1 and iPadOS 14.8.1, iOS 15.1 and iPadOS 15.1. A malicious application may be able to execute arbitrary code with kernel privileges.

Affected Products

3 products · 5 configurations

ipadosapple

< 14.8.1

1 version

15.0

iphone osapple

< 14.8.1

1 version

15.0

macosapple

< 11.6.1

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

An out-of-bounds write issue was addressed with improved bounds checking…

cisa.govCISAMar 2023

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-30900 in your stack?

O3 detects CVE-2021-30900 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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