CVE-2021-30663

mediumpriority · act · 90OT risk · criticalKEV · exploitedEPSS 0.035 · 89 %ileEURUUS

grimoire priorityP0 · Act now

Exploitable?

Yes · in the wild

CISA KEV

Likely / severe?

3.52% (89th) EPSS

CVSS 6.8 · medium

Is it mine?

29 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · fstec_bdu

added 2021-11-03remediate by 2021-11-17

required action Apply updates per vendor instructions.

EPSS · scored 2026-10-24

Apple Multiple Products WebKit Integer Overflow Vulnerability

An integer overflow was addressed with improved input validation. This issue is fixed in iOS 14.5.1 and iPadOS 14.5.1, tvOS 14.6, iOS 12.5.3, Safari 14.1.1, macOS Big Sur 11.3.1. Processing maliciously crafted web content may lead to arbitrary code execution.

cvss

Technical severity, 0–10. One row per scoring source.

8.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.8–8.8

v2.06.8mediumAV:N/AC:M/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 8.6 · impact 6.4

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 2.8 · impact 5.9

v3.18.8highAV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:Hsecondary · ENISA EU

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:Hsecondaryexploitability 1.8 · impact 5.9

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:Hsecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: active · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-190USprimaryCWE-190US

affected products (29)

Products and version ranges known to be affected.

Apple macOSunspecified → 11.3enisa_euvdEU
Apple macOSunspecified → 12.5enisa_euvdEU
Apple macOSunspecified → 14.1enisa_euvdEU
Apple macOSunspecified → 14.5enisa_euvdEU
Apple macOSunspecified → 14.6enisa_euvdEU
Apple Inc. MacOS11.0 → 11.3.1fstec_bduRU
Apple Inc. Safari≤ 14.1.1fstec_bduRU
Apple Inc. iOS14.0 → 14.5.1fstec_bduRU
Apple Inc. iPadOS14.0 → 14.5.1fstec_bduRU
Apple Inc. tvOS≤ 14.6fstec_bduRU
Canonical Ltd. Ubuntu≤ 21.04fstec_bduRU
Canonical Ltd. Ubuntu≤ 18.04 LTSfstec_bduRU
Canonical Ltd. Ubuntu≤ 20.04 LTSfstec_bduRU
Fedora Project Fedora≤ 34fstec_bduRU
Fedora Project Fedora≤ 33fstec_bduRU
Novell Inc. OpenSUSE Leap≤ 15.3fstec_bduRU
Red Hat Inc. Red Hat Enterprise Linux≤ 8fstec_bduRU
АО «НППКТ» ОСОН ОСнова Оnyx≤ 2.1fstec_bduRU
ООО «РусБИТех-Астра» Astra Linux Special Edition≤ 1.7fstec_bduRU
ООО «РусБИТех-Астра» Astra Linux Special Edition≤ 4.7fstec_bduRU

showing 20 of 29

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu NVD CVE.org MITRE

published 2021-09-08modified 2026-06-17

related (4,629)

Related entries.

ID	severity	EPSS	exploitable	published
CVE-2025-48595US	—OT critical	1.71% (77th)	KEV	2026-06-01
In multiple locations, there is a possible way to achieve code execution due to an integer overflow. This could lead to local escalation of privilege with no additional execution p…
CVE-2026-21385US	—OT critical	1.29% (70th)	KEV	2026-03-02
Memory corruption while using alignments for memory allocation.
CVE-2025-24985US	—OT critical	3.89% (90th)	KEV	2025-03-11
Integer overflow or wraparound in Windows Fast FAT Driver allows an unauthorized attacker to execute code locally.
CVE-2024-38080US	—OT critical	7.12% (94th)	KEV	2024-07-09
Windows Hyper-V Elevation of Privilege Vulnerability
CVE-2023-33107US	high7.8OT critical	0.74% (54th)	KEV	2023-12-05
Memory corruption in Graphics Linux while assigning shared virtual memory region during IOCTL call.

+4624 more

references (39)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan