{"cve":"CVE-2021-26271","nvd":{"published":"2021-01-26T21:15:12.860","modified":"2026-08-25T16:28:27.310","status":"Modified","description":"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).","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","score":6.5},"cwes":["CWE-829"],"references":["https://ckeditor.com/blog/CKEditor-4.16-with-improved-image-pasting-High-Contrast-support-and-a-new-color-API/#security-comes-first","https://github.com/ckeditor/ckeditor4/blob/major/CHANGES.md#ckeditor-416","https://www.oracle.com//security-alerts/cpujul2021.html","https://www.oracle.com/security-alerts/cpuoct2021.html","https://ckeditor.com/blog/CKEditor-4.16-with-improved-image-pasting-High-Contrast-support-and-a-new-color-API/#security-comes-first"],"products":["ckeditor:ckeditor","oracle:agile_product_lifecycle_management","oracle:application_express","oracle:financial_services_analytical_applications_infrastructure","oracle:jd_edwards_enterpriseone_tools","oracle:siebel_ui_framework","oracle:webcenter_sites"],"source":"nvd","synced_at":"2026-10-19T21:14:10.479542811+00:00"},"epss":{"cve":"CVE-2021-26271","score":0.01994,"percentile":0.80697,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-jv4c-7jqq-m34x","url":"https://osv.dev/vulnerability/GHSA-jv4c-7jqq-m34x","summary":"CKEditor 4 ReDoS Vulnerability","modified":"2026-09-10T03:49:39.067777385Z","packages":[{"ecosystem":"npm","name":"ckeditor4-dev","purl":"pkg:npm/ckeditor4-dev","ranges":["<4.16"],"fixed":["4.16"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}