CVEvulnerability

CVE-2021-29503

6.1 MEDIUM Published 2021-05-19 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2021-05-19
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
8.1 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
CVSS 3.1 ([email protected])
6.1 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS 2.0 ([email protected])
4.3 MEDIUM — AV:N/AC:M/Au:N/C:N/I:P/A:N
Weaknesses
CWE-79, CWE-80

Description

HedgeDoc is a platform to write and share markdown. HedgeDoc before version 1.8.2 is vulnerable to a cross-site scripting attack using the YAML-metadata of a note. An attacker with write access to a note can embed HTML tags in the Open Graph metadata section of the note, resulting in the frontend rendering the script tag as part of the `<head>` section. Unless your instance prevents guests from editing notes, this vulnerability allows unauthenticated attackers to inject JavaScript into notes that allow guest edits. If your instance prevents guests from editing notes, this vulnerability allows authenticated attackers to inject JavaScript into any note pages they have write-access to. This vulnerability is patched in version 1.8.2. As a workaround, one can disable guest edits until the next update.

Affected configurations

• hedgedoc hedgedoc (< 1.8.2)

Related

Weakness · CWE (2)

  • CWE-79 Improper Neutralization of Input During Web Page Generation weakness
  • CWE-80 Improper Neutralization of Script-Related HTML Tags in a Web Page weakness

References