CVEvulnerability
CVE-2021-21259
6.1 MEDIUM
Official page ↗
- Status
- Modified
- Published
- 2021-01-22
- Last modified
- 2026-06-17
- Assigner
- [email protected]
- CVSS 3.1 ([email protected])
- 7.4 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/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
Description
HedgeDoc is open source software which lets you create real-time collaborative markdown notes. In HedgeDoc before version 1.7.2, an attacker can inject arbitrary JavaScript into a HedgeDoc note, which is executed when the note is viewed in slide mode. Depending on the configuration of the instance, the attacker may not need authentication to create or edit notes. The problem is patched in HedgeDoc 1.7.2. As a workaround, disallow loading JavaScript from 3rd party sites using the `Content-Security-Policy` header. Note that this will break some embedded content.
Affected configurations
• hedgedoc hedgedoc (< 1.7.2)
Related
Weakness · CWE (1)
- CWE-79 Improper Neutralization of Input During Web Page Generation weakness
References
- https://github.com/hackmdio/codimd/issues/1648 Exploit, Patch, Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/commit/35b0d39a12aa35f27fba8c1f50b1886706e7efef Patch, Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/releases/tag/1.7.2 Release Notes, Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-44w9-vm8p-3cxw Third Party Advisory
- https://github.com/hackmdio/codimd/issues/1648 Exploit, Patch, Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/commit/35b0d39a12aa35f27fba8c1f50b1886706e7efef Patch, Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/releases/tag/1.7.2 Release Notes, Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-44w9-vm8p-3cxw Third Party Advisory