{"cve":"CVE-2020-26211","nvd":{"published":"2020-11-03T21:15:12.547","modified":"2026-06-17T03:07:49.867","status":"Modified","description":"In BookStack before version 0.30.4, a user with permissions to edit a page could insert JavaScript code through the use of `javascript:` URIs within a link or form which would run, within the context of the current page, when clicked or submitted. Additionally, a user with permissions to edit a page could insert a particular meta tag which could be used to silently redirect users to a alternative location upon visit of a page. Dangerous content may remain in the database but will be removed before being displayed on a page. If you think this could have been exploited the linked advisory provides a SQL query to test. As a workaround without upgrading, page edit permissions could be limited to only those that are trusted until you can upgrade although this will not address existing exploitation of this vulnerability. The issue is fixed in BookStack version 0.30.4.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N","score":8.7},"cwes":["CWE-79"],"references":["https://github.com/BookStackApp/BookStack/commit/bbd1384acbe7e52c21f89af69f2dc391c95dbf54","https://github.com/BookStackApp/BookStack/releases/tag/v0.30.4","https://github.com/BookStackApp/BookStack/security/advisories/GHSA-r2cf-8778-3jgp","https://www.bookstackapp.com/blog/beta-release-v0-30-4/","https://github.com/BookStackApp/BookStack/commit/bbd1384acbe7e52c21f89af69f2dc391c95dbf54"],"products":["bookstackapp:bookstack"],"source":"nvd","synced_at":"2026-10-19T21:11:20.317016139+00:00"},"epss":{"cve":"CVE-2020-26211","score":0.01096,"percentile":0.65576,"date":"2026-10-31"},"kev":null,"osv":[],"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."]}