Uncaught Exception in HedgeDoc - #VU165820
Published: November 11, 2026
Vulnerability identifier: #VU165820
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-248
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service by crashing the HedgeDoc server process.
The vulnerability exists due to an uncaught exception in the WebSocket selection handler in lib/ot/editor-socketio-server.js when processing invalid editor selection ranges. A remote attacker can send specially crafted selection data for a note they can edit to trigger a type error during conversion by Range.fromJSON in lib/ot/selection.js, terminating the Node.js process and making the entire instance temporarily unavailable.
Affected software
HedgeDoc
Remediation
Install security update from vendor's website.
HedgeDoc - update to 1.12.1