CVE-2021-21259
mediumpriority · track · 24EPSS 0.014 · 72 %ileEUUSEPSS · scored 2026-10-27
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.3–7.4
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (2)
Products and version ranges known to be affected.
also known as (2)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (13)
External citations — patches, advisories, analysis.
- https://github.com/hackmdio/codimd/issues/1648cnnvd
- https://github.com/hedgedoc/hedgedoc/commit/35b0d39a12aa35f27fba8c1f50b1886706e7efefcnnvd
- https://github.com/hedgedoc/hedgedoc/releases/tag/1.7.2cnnvd
- https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-44w9-vm8p-3cxwcnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2021-21259cnnvd
- https://github.com/hackmdio/codimd/issues/1648enisa_euvd
- https://github.com/hedgedoc/hedgedoc/commit/35b0d39a12aa35f27fba8c1f50b1886706e7efefenisa_euvd
- https://github.com/hedgedoc/hedgedoc/releases/tag/1.7.2enisa_euvd
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