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Vulnerability details: VCID-7jce-ugzg-n3g7
Vulnerability ID VCID-7jce-ugzg-n3g7
Aliases CVE-2021-30666
Summary A buffer overflow issue was addressed with improved memory handling. This issue is fixed in iOS 12.5.3. 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..
Status Published
Exploitability 2.0
Weighted Severity 8.0
Risk 10.0
Affected and Fixed Packages Package Details
Weaknesses (2)
CWE-20 Improper Input Validation
CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
System Score Found at
cvssv3 8.8 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-30666.json
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
epss 0.00901 https://api.first.org/data/v1/epss?cve=CVE-2021-30666
cvssv2 6.8 https://nvd.nist.gov/vuln/detail/CVE-2021-30666
cvssv3.1 8.8 https://nvd.nist.gov/vuln/detail/CVE-2021-30666
archlinux High https://security.archlinux.org/AVG-2210
archlinux High https://security.archlinux.org/AVG-2211
cvssv3.1 8.8 https://support.apple.com/en-us/HT212341
ssvc Attend https://support.apple.com/en-us/HT212341
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-30666.json
https://api.first.org/data/v1/epss?cve=CVE-2021-30666
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8625
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8710
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8720
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8743
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8764
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8766
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8769
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8771
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8782
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8783
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8808
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8811
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8813
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8815
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8816
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8819
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8820
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8823
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-30666
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-30761
1986877 https://bugzilla.redhat.com/show_bug.cgi?id=1986877
AVG-2210 https://security.archlinux.org/AVG-2210
AVG-2211 https://security.archlinux.org/AVG-2211
cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
CVE-2021-30666 https://nvd.nist.gov/vuln/detail/CVE-2021-30666
HT212341 https://support.apple.com/en-us/HT212341
RHSA-2020:4035 https://access.redhat.com/errata/RHSA-2020:4035
RHSA-2020:4451 https://access.redhat.com/errata/RHSA-2020:4451
RHSA-2025:10364 https://access.redhat.com/errata/RHSA-2025:10364
Data source KEV
Date added Nov. 3, 2021
Description Apple iOS WebKit contains a buffer-overflow vulnerability that leads to code execution when processing maliciously crafted web content. This vulnerability could impact HTML parsers that use WebKit, including but not limited to Apple Safari and non-Apple products which rely on WebKit for HTML processing.
Required action Apply updates per vendor instructions.
Due date Nov. 17, 2021
Note 
https://nvd.nist.gov/vuln/detail/CVE-2021-30666
Ransomware campaign use Unknown
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-30666.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: AV:N/AC:M/Au:N/C:P/I:P/A:P Found at https://nvd.nist.gov/vuln/detail/CVE-2021-30666
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2021-30666
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Found at https://support.apple.com/en-us/HT212341
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:A/A:N/T:T/P:M/B:A/M:M/D:A/2025-01-29T17:25:57Z/ Found at https://support.apple.com/en-us/HT212341
Exploit Prediction Scoring System (EPSS)
Percentile 0.74726
EPSS Score 0.00901
Published At July 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:33:15.371733+00:00 Alpine Linux Importer Import https://secdb.alpinelinux.org/v3.20/community.json 37.0.0