PT-2020-16405 · Hedgedoc+1 · Hedgedoc+2

Alemmi · Published 2020-12-28 · Updated 2020-12-30 · CVE-2020-26287

Positive Technologies (AI Summary)

CVSS v3.1

8.7

High

Base vector

AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

Name of the Vulnerable Software and Affected Versions HedgeDoc versions prior to 1.7.1

Description The issue allows an attacker to inject arbitrary script tags in HedgeDoc notes using mermaid diagrams. Although the content security policy prevents loading scripts from most locations, www.google-analytics.com is allowed, which can be exploited using Google Tag Manager to inject arbitrary JavaScript and execute it on page load. Depending on the instance configuration, the attacker may not need authentication to create or edit notes.

Recommendations For HedgeDoc versions prior to 1.7.1, update to version 1.7.1 to resolve the issue. As a temporary workaround, consider disallowing www.google-analytics.com in the Content-Security-Policy header to minimize the risk of exploitation.

Exploit

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2020-26287

GHSA-G6W6-7XF9-M95P

Affected Products

Google Analytics

Google Tag Manager

Hedgedoc

References · 8

• 🔥 https://github.com/Alemmi/ctf-writeups/blob/main/hxpctf-2020/hackme/solution.md · Exploit
• https://github.com/hedgedoc/hedgedoc/commit/58276ebbf4504a682454a3686dcaff88bc1069d4 · Patch
• https://osv.dev/vulnerability/CVE-2020-26287 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2020-26287 · Security Note
• https://github.com/hackmdio/codimd/issues/1630 · Note
• https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-g6w6-7xf9-m95p · Note
• https://github.com/hedgedoc/hedgedoc/releases/tag/1.7.1 · Note
• https://t.me/cvenotify/7857 · Telegram Post