{"cve":"CVE-2020-26287","nvd":{"published":"2020-12-29T00:15:12.673","modified":"2026-06-17T03:08:00.227","status":"Modified","description":"HedgeDoc is a collaborative platform for writing and sharing markdown. In HedgeDoc before version 1.7.1 an attacker can inject arbitrary `script` tags in HedgeDoc notes using mermaid diagrams. Our content security policy prevents loading scripts from most locations, but `www.google-analytics.com` is allowed. Using Google Tag Manger it is possible to inject arbitrary JavaScript and execute it on page load. Depending on the configuration of the instance, the attacker may not need authentication to create or edit notes. The problem is patched in HedgeDoc 1.7.1. As a workaround one can disallow `www.google-analytics.com` in the `Content-Security-Policy` header. Note that other ways to leverage the `script` tag injection might exist.","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/Alemmi/ctf-writeups/blob/main/hxpctf-2020/hackme/solution.md","https://github.com/hackmdio/codimd/issues/1630","https://github.com/hedgedoc/hedgedoc/commit/58276ebbf4504a682454a3686dcaff88bc1069d4","https://github.com/hedgedoc/hedgedoc/releases/tag/1.7.1","https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-g6w6-7xf9-m95p"],"products":["hedgedoc:hedgedoc"],"source":"nvd","synced_at":"2026-10-19T21:12:09.559580076+00:00"},"epss":{"cve":"CVE-2020-26287","score":0.01464,"percentile":0.73639,"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."]}