CVE-2021-30661: Apple Multiple Products WebKit Storage Use-After-Free Vulnerability
Vulnerability summary
CVE-2021-30661 is a high (CVSS 8.8) Use After Free vulnerability in Apple Multiple Products. It is known to be exploited: CISA lists it, first on 03-11-2021. EPSS estimates a 4.49% chance of exploitation in the next 30 days, higher than 91.3% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 9 · Related 6Timeline
- 08-09-2021PublishedVulnerability first disclosed.
- 03-11-2021Added to CISA KEVApple Multiple Products WebKit Storage Use-After-Free Vulnerability
- 17-11-2021CISA remediation dueApply updates per vendor instructions.
- 21-10-2025Last modifiedVulnerability information updated.
Description
A use after free issue was addressed with improved memory management. This issue is fixed in Safari 14.1, iOS 12.5.3, iOS 14.5 and iPadOS 14.5, watchOS 7.4, tvOS 14.5, macOS Big Sur 11.3. Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- NVDNIST8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS trend
Probability
4.49%
Chance of exploitation in the next 30 days
Percentile
91%
Versus all other CVEs
30-day change
0.00 pp
From 4.49% on 19-09-2026
Known exploited
Compare KEV catalogs
CISA KEVListed- Added
- 03-11-2021
- Federal due date
- 17-11-2021
CISA required action
Apply updates per vendor instructions. nvd.nist.gov/vuln/detail/CVE-2021-30661
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Apple7 products
- ios and ipados≥ unspecified, < 14.5
- ipados< 14.5
- iphone_os< 12.5.3 | ≥ 14.0, < 14.5
- macos≥ unspecified, < 11.3 | ≥ unspecified, < 12.5 | ≥ 11.0, < 11.3
- safari≥ unspecified, < 14.1 | < 14.1
Ubuntu5 products
- qtwebkit-opensource-srcAll versions (No fix recorded)
- qtwebkit-sourceAll versions (No fix recorded)
- webkit2gtkAll versions (No fix recorded) | < 2.30.3-0ubuntu0.18.04.1 | < 2.30.3-0ubuntu0.20.04.1
- webkitgtkAll versions (No fix recorded)
- wpewebkitAll versions (No fix recorded)
Debian2 products
- webkit2gtk< 2.30.1-1
- wpewebkit< 2.30.0-1
3 vendors · 14 products
References
11 links- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30661Government ResourceThird Party AdvisoryUS Government Resource
