# CVE-2021-30761: Apple iOS WebKit Memory Corruption Vulnerability

Source: https://junglewise.ai/threats/cve-2021-30761-apple-ios-webkit-memory-corruption-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2021-11-03. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-2021-30761 · Severity: critical · CVSS 8.8 · Exploited in the wild · Published 2021-11-03

Apple iOS WebKit contains a memory corruption vulnerability (specifically an out-of-bounds write) when processing maliciously crafted web content. Successful exploitation allows for arbitrary code execution on the affected device. Apple has acknowledged reports that this vulnerability may have been actively exploited in the wild.

## Quick answers

**Is CVE-2021-30761 exploited in the wild?** Yes. CVE-2021-30761 is known to be exploited in the wild, first recorded on 3 November 2021. Treat it as urgent.

**How severe is CVE-2021-30761?** Critical severity, with a CVSS score of 8.8, published 3 November 2021.

**Which products and versions are affected?** Apple iOS up to (excluding) 12.5.4; Apple WebKit.

**Is there a fix for CVE-2021-30761?** A patch was published on 2021-06-14: Issue addressed in iOS 12.5.4 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2021-30761 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2021-30761?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Apple iOS up to (excluding) 12.5.4
- Apple WebKit

## Timeline

- 2021-06-14: patched: Issue addressed in iOS 12.5.4
- 2021-09-08: disclosed: NVD Published Date
- 2021-11-03: kev added: Date added to CISA Known Exploited Vulnerabilities Catalog
- 2021-11-03: exploited: Apple reported awareness of active exploitation.