David Mehren

4 exploits Active since Dec 2020
CVE-2020-26286 WRITEUP HIGH WRITEUP
HedgeDoc <1.7.1 - Unauthenticated 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.
CVSS 7.5
CVE-2020-26287 WRITEUP HIGH WRITEUP
HedgeDoc <1.7.1 - XSS
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.
CVSS 8.7
CVE-2021-29503 WRITEUP HIGH WRITEUP
Hedgedoc < 1.8.2 - Basic XSS
HedgeDoc is a platform to write and share markdown. HedgeDoc before version 1.8.2 is vulnerable to a cross-site scripting attack using the YAML-metadata of a note. An attacker with write access to a note can embed HTML tags in the Open Graph metadata section of the note, resulting in the frontend rendering the script tag as part of the `<head>` section. Unless your instance prevents guests from editing notes, this vulnerability allows unauthenticated attackers to inject JavaScript into notes that allow guest edits. If your instance prevents guests from editing notes, this vulnerability allows authenticated attackers to inject JavaScript into any note pages they have write-access to. This vulnerability is patched in version 1.8.2. As a workaround, one can disable guest edits until the next update.
CVSS 8.1
CVE-2024-45308 WRITEUP MEDIUM WRITEUP
HedgeDoc 1 - Info Disclosure
HedgeDoc is an open source, real-time, collaborative, markdown notes application. When using HedgeDoc 1 with MySQL or MariaDB, it is possible to create notes with an alias matching the ID of existing notes. The affected existing note can then not be accessed anymore and is effectively hidden by the new one. When the freeURL feature is enabled (by setting the `allowFreeURL` config option or the `CMD_ALLOW_FREEURL` environment variable to `true`), any user with the appropriate permissions can create a note with an arbitrary alias, e.g. by accessing it in the browser. When MySQL or MariaDB are used, it is possible to create a new note with an alias that matches the lower-cased ID of a different note. HedgeDoc then always presents the new note to users, as these databases perform case-insensitive matching and the lower-cased alias is found first. This issue only affects HedgeDoc instances that use MySQL or MariaDB. Depending on the permission settings of the HedgeDoc instance, the issue can be exploited only by logged-in users or by all (including non-logged-in) users. The exploit requires knowledge of the ID of the target note. Attackers could use this issue to present a manipulated copy of the original note to the user, e.g. by replacing the links with malicious ones. Attackers can also use this issue to prevent access to the original note, causing a denial of service. No data is lost, as the original content of the affected notes is still present in the database. Users are advised to upgrade to version 1.10.0 which addresses this issue. Users unable to upgrade may disable freeURL mode which prevents the exploitation of this issue. The impact can also be limited by restricting freeURL note creation to trusted, logged-in users by enabling `requireFreeURLAuthentication`/`CMD_REQUIRE_FREEURL_AUTHENTICATION`.
CVSS 6.5