CVE-2020-26286
Arbitary file upload
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Arbitary file upload
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.
- Record
CVE-2020-26286- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-434
- Updated
- 2026-11-02
EUVDEUVD-2020-18854
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.
- Record
EUVD-2020-18854- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-03
NVD
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.
- Record
CVE-2020-26286- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:P/A:N - Weakness
- CWE-434
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2020-26286- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-26286 is a high vulnerability (CVSS 7.5) in Hedgedoc, published December 28, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.44%, the 73rd percentile. No source names a fixed version.