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CVE-2020-26287

HighCVSS 8.7 / 10
Published Dec 29, 2020·Last modified Mar 15, 2026
Affected Components(0)

No affected components available

Description

HedgeDoc is a collaborative platform for writing and sharing markdown. In HedgeDoc before version 1.7.1 an attacker can inject arbitrary script tags in HedgeDoc notes using mermaid diagrams. Our content security policy prevents loading scripts from most locations, but www.google-analytics.com is allowed. Using Google Tag Manger it is possible to inject arbitrary JavaScript and execute it on page load. Depending on the configuration of the instance, the attacker may not need authentication to create or edit notes. The problem is patched in HedgeDoc 1.7.1. As a workaround one can disallow www.google-analytics.com in the Content-Security-Policy header. Note that other ways to leverage the script tag injection might exist.

Risk Scores
Base Score
8.7

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. The attacker needs the user to perform some action, like clicking a link. The vulnerability can affect other systems as well, not just the initial system. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data.

Threat Intelligence
8.0

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
1.45%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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