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Vulnerability details: VCID-gqad-5dqp-37g2
Vulnerability ID VCID-gqad-5dqp-37g2
Aliases CVE-2021-26271
GHSA-jv4c-7jqq-m34x
Summary CKEditor 4 ReDoS Vulnerability It was possible to execute a ReDoS-type attack inside CKEditor 4 before 4.16 by persuading a victim to paste crafted text into the Styles input of specific dialogs (in the Advanced Tab for Dialogs plugin).
Status Published
Exploitability 0.5
Weighted Severity 6.2
Risk 3.1
Affected and Fixed Packages Package Details
Weaknesses (4)
CWE-1333 Inefficient Regular Expression Complexity
CWE-829 Inclusion of Functionality from Untrusted Control Sphere
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
epss 0.00639 https://api.first.org/data/v1/epss?cve=CVE-2021-26271
cvssv3.1_qr MODERATE https://github.com/advisories/GHSA-jv4c-7jqq-m34x
cvssv3.1 6.5 https://github.com/ckeditor/ckeditor4
generic_textual MODERATE https://github.com/ckeditor/ckeditor4
cvssv3.1 6.5 https://github.com/ckeditor/ckeditor4/blob/major/CHANGES.md#ckeditor-416
generic_textual MODERATE https://github.com/ckeditor/ckeditor4/blob/major/CHANGES.md#ckeditor-416
cvssv2 4.3 https://nvd.nist.gov/vuln/detail/CVE-2021-26271
cvssv3.1 6.5 https://nvd.nist.gov/vuln/detail/CVE-2021-26271
generic_textual MODERATE https://nvd.nist.gov/vuln/detail/CVE-2021-26271
cvssv3.1 6.5 https://web.archive.org/web/20210128132707/https://ckeditor.com/blog/CKEditor-4.16-with-improved-image-pasting-High-Contrast-support-and-a-new-color-API/#security-comes-first
generic_textual MODERATE https://web.archive.org/web/20210128132707/https://ckeditor.com/blog/CKEditor-4.16-with-improved-image-pasting-High-Contrast-support-and-a-new-color-API/#security-comes-first
cvssv3.1 6.5 https://www.oracle.com//security-alerts/cpujul2021.html
generic_textual MODERATE https://www.oracle.com//security-alerts/cpujul2021.html
cvssv3.1 6.5 https://www.oracle.com/security-alerts/cpuoct2021.html
generic_textual MODERATE https://www.oracle.com/security-alerts/cpuoct2021.html
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2021-26271
https://ckeditor.com/blog/CKEditor-4.16-with-improved-image-pasting-High-Contrast-support-and-a-new-color-API/#security-comes-first
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-26271
https://github.com/ckeditor/ckeditor4
https://github.com/ckeditor/ckeditor4/blob/major/CHANGES.md#ckeditor-416
https://nvd.nist.gov/vuln/detail/CVE-2021-26271
https://web.archive.org/web/20210128132707/https://ckeditor.com/blog/CKEditor-4.16-with-improved-image-pasting-High-Contrast-support-and-a-new-color-API/#security-comes-first
https://www.oracle.com//security-alerts/cpujul2021.html
https://www.oracle.com/security-alerts/cpuoct2021.html
982587 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=982587
cpe:2.3:a:ckeditor:ckeditor:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:ckeditor:ckeditor:*:*:*:*:*:*:*:*
cpe:2.3:a:oracle:agile_plm:9.3.5:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:agile_plm:9.3.5:*:*:*:*:*:*:*
cpe:2.3:a:oracle:agile_plm:9.3.6:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:agile_plm:9.3.6:*:*:*:*:*:*:*
cpe:2.3:a:oracle:application_express:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:application_express:*:*:*:*:*:*:*:*
cpe:2.3:a:oracle:financial_services_analytical_applications_infrastructure:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:financial_services_analytical_applications_infrastructure:*:*:*:*:*:*:*:*
cpe:2.3:a:oracle:financial_services_analytical_applications_infrastructure:8.1.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:financial_services_analytical_applications_infrastructure:8.1.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:financial_services_analytical_applications_infrastructure:8.1.1:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:financial_services_analytical_applications_infrastructure:8.1.1:*:*:*:*:*:*:*
cpe:2.3:a:oracle:jd_edwards_enterpriseone_tools:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:jd_edwards_enterpriseone_tools:*:*:*:*:*:*:*:*
cpe:2.3:a:oracle:siebel_ui_framework:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:siebel_ui_framework:*:*:*:*:*:*:*:*
cpe:2.3:a:oracle:webcenter_sites:12.2.1.3.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:webcenter_sites:12.2.1.3.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:webcenter_sites:12.2.1.4.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:webcenter_sites:12.2.1.4.0:*:*:*:*:*:*:*
GHSA-jv4c-7jqq-m34x https://github.com/advisories/GHSA-jv4c-7jqq-m34x
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Found at https://github.com/ckeditor/ckeditor4
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:N/I:N/A:H Found at https://github.com/ckeditor/ckeditor4/blob/major/CHANGES.md#ckeditor-416
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:N/I:N/A:P Found at https://nvd.nist.gov/vuln/detail/CVE-2021-26271
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:N/I:N/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2021-26271
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:N/I:N/A:H Found at https://web.archive.org/web/20210128132707/https://ckeditor.com/blog/CKEditor-4.16-with-improved-image-pasting-High-Contrast-support-and-a-new-color-API/#security-comes-first
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:N/I:N/A:H Found at https://www.oracle.com//security-alerts/cpujul2021.html
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:N/I:N/A:H Found at https://www.oracle.com/security-alerts/cpuoct2021.html
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
Exploit Prediction Scoring System (EPSS)
Percentile 0.69524
EPSS Score 0.00639
Published At June 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-01T12:28:50.752444+00:00 GithubOSV Importer Import https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2022/05/GHSA-jv4c-7jqq-m34x/GHSA-jv4c-7jqq-m34x.json 36.1.3