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Vulnerability details: VCID-z8xq-1jky-37eq
Vulnerability ID VCID-z8xq-1jky-37eq
Aliases CVE-2021-30661
Summary 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..
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-416 Use After Free
System Score Found at
cvssv3 8.8 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-30661.json
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
epss 0.00218 https://api.first.org/data/v1/epss?cve=CVE-2021-30661
cvssv2 6.8 https://nvd.nist.gov/vuln/detail/CVE-2021-30661
cvssv3.1 8.8 https://nvd.nist.gov/vuln/detail/CVE-2021-30661
archlinux High https://security.archlinux.org/AVG-2208
archlinux High https://security.archlinux.org/AVG-2209
cvssv3.1 8.8 https://support.apple.com/en-us/HT212317
ssvc Attend https://support.apple.com/en-us/HT212317
cvssv3.1 8.8 https://support.apple.com/en-us/HT212318
ssvc Attend https://support.apple.com/en-us/HT212318
cvssv3.1 8.8 https://support.apple.com/en-us/HT212323
ssvc Attend https://support.apple.com/en-us/HT212323
cvssv3.1 8.8 https://support.apple.com/en-us/HT212324
ssvc Attend https://support.apple.com/en-us/HT212324
cvssv3.1 8.8 https://support.apple.com/en-us/HT212325
ssvc Attend https://support.apple.com/en-us/HT212325
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-2021-30661.json
https://api.first.org/data/v1/epss?cve=CVE-2021-30661
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-13543
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-13584
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-9947
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-9948
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-9951
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-9983
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-1817
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-1820
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-1825
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-1826
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-30661
1986870 https://bugzilla.redhat.com/show_bug.cgi?id=1986870
AVG-2208 https://security.archlinux.org/AVG-2208
AVG-2209 https://security.archlinux.org/AVG-2209
cpe:2.3:a:apple:safari:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:apple:safari:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:ipados:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:apple:ipados:*:*:*:*:*:*:*:*
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:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:tvos:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:apple:tvos:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:watchos:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:apple:watchos:*:*:*:*:*:*:*:*
CVE-2021-30661 https://nvd.nist.gov/vuln/detail/CVE-2021-30661
HT212317 https://support.apple.com/en-us/HT212317
HT212318 https://support.apple.com/en-us/HT212318
HT212323 https://support.apple.com/en-us/HT212323
HT212324 https://support.apple.com/en-us/HT212324
HT212325 https://support.apple.com/en-us/HT212325
HT212341 https://support.apple.com/en-us/HT212341
RHSA-2021:1586 https://access.redhat.com/errata/RHSA-2021:1586
RHSA-2025:10364 https://access.redhat.com/errata/RHSA-2025:10364
Data source KEV
Date added Nov. 3, 2021
Description Apple iOS, iPadOS, macOS, tvOS, watchOS, and Safari WebKit Storage contain a use-after-free 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-2021-30661
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-2021-30661.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-2021-30661
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-2021-30661
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/HT212317
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/2025-01-29T17:25:03Z/ Found at https://support.apple.com/en-us/HT212317
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/HT212318
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/2025-01-29T17:25:03Z/ Found at https://support.apple.com/en-us/HT212318
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/HT212323
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/2025-01-29T17:25:03Z/ Found at https://support.apple.com/en-us/HT212323
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/HT212324
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/2025-01-29T17:25:03Z/ Found at https://support.apple.com/en-us/HT212324
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/HT212325
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/2025-01-29T17:25:03Z/ Found at https://support.apple.com/en-us/HT212325
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/2025-01-29T17:25:03Z/ Found at https://support.apple.com/en-us/HT212341
Exploit Prediction Scoring System (EPSS)
Percentile 0.44485
EPSS Score 0.00218
Published At July 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:54:18.825030+00:00 Alpine Linux Importer Import https://secdb.alpinelinux.org/v3.18/community.json 37.0.0