CVE-2021-21259
Last modified
CVE-2021-21259 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. 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. EPSS estimates a 1.35% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Hedgedoc | Hedgedoc | < 1.7.2 |
References
- https://github.com/hackmdio/codimd/issues/1648Exploit, Patch, Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/commit/35b0d39a12aa35f27fba8c1f50b1886706e7efefPatch, Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/releases/tag/1.7.2Release Notes, Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-44w9-vm8p-3cxwThird Party Advisory
- https://github.com/hackmdio/codimd/issues/1648Exploit, Patch, Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/commit/35b0d39a12aa35f27fba8c1f50b1886706e7efefPatch, Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/releases/tag/1.7.2Release Notes, Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-44w9-vm8p-3cxwThird Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
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How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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