Improper Neutralization of Script-Related HTML Tags in Notes
CVE-2021-29503

8.1HIGH

Key Information:

Vendor

Hedgedoc

Status
Hedgedoc
Vendor
CVE Published:
19 May 2021

What is CVE-2021-29503?

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.

Affected Version(s)

hedgedoc < 1.8.2

References

https://github.com/hedgedoc/hedgedoc/security/advisories/...
x_refsource_CONFIRM
https://github.com/hedgedoc/hedgedoc/commit/01dad5821ee28...
x_refsource_MISC
https://github.com/hedgedoc/hedgedoc/releases/tag/1.8.2
x_refsource_MISC

CVSS V3.1

Score:
8.1
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.