What’s Vulnerable › Vulnerabilities

CVE-2020-26286: Arbitary file upload

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-12-29 · updated 2026-06-17
• Weakness: CWE-434

Description

HedgeDoc is a collaborative platform for writing and sharing markdown. In HedgeDoc before version 1.7.1 an unauthenticated attacker can upload arbitrary files to the upload storage backend including HTML, JS and PHP files. The problem is patched in HedgeDoc 1.7.1. You should however verify that your uploaded file storage only contains files that are allowed, as uploaded files might still be served. As workaround it's possible to block the `/uploadimage` endpoint on your instance using your reverse proxy. And/or restrict MIME-types and file names served from your upload file storage.

Affected products

• hedgedoc: before 1.7.1 — fixed in 1.7.1

How to fix

Upgrade to a fixed version: hedgedoc 1.7.1. Check the vendor advisory for mitigations.

References

• https://github.com/hedgedoc/hedgedoc/commit/e9306991cdb5ff2752c1eeba3fedba42aec3c2d8
• https://github.com/hedgedoc/hedgedoc/releases/tag/1.7.1
• https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-wcr3-xhv7-8gxc
• https://github.com/hedgedoc/hedgedoc/commit/e9306991cdb5ff2752c1eeba3fedba42aec3c2d8
• https://github.com/hedgedoc/hedgedoc/releases/tag/1.7.1
• https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-wcr3-xhv7-8gxc

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