High severity · published Apr 21, 2026
CVE-2026-39320
Signal K Server has an Unauthenticated Regular Expression Denial of Service (ReDoS) via WebSocket Subscription Paths
7.5
CVSS
0.4%
EPSS
No
On KEV
Description
Signal K Server is a server application that runs on a central hub in a boat. Versions prior to 2.25.0 are vulnerable to an unauthenticated Regular Expression Denial of Service (ReDoS) attack within the WebSocket subscription handling logic. By injecting unescaped regex metacharacters into the `context` parameter of a stream subscription, an attacker can force the server's Node.js event loop into a catastrophic backtracking loop when evaluating long string identifiers (like the server's self UUID). This results in a total Denial of Service (DoS) where the server CPU spikes to 100% and becomes completely unresponsive to further API or socket requests. Version 2.25.0 contains a fix.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 37% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SI
signalk-server · SignalK
< 2.25.0 · source: vendor
SK
Signal K Server · Signalk
before 2.25.0 · source: NVD
Affected product
SI
signalk-server
SignalK
More from signalk-server
9.8
CVE-2026-118690
Signal K Server before 2.33.0 Missing Authentication via /skServer/ziplogs
9.4
CVE-2026-33950
signalk-server: Privilege Escalation by Admin Role Injection via /enableSecurity
9.1
CVE-2025-68620
Signal K Server vulnerable to JWT Token Theft via WebSocket Enumeration and Unauthenticated Polling
8.8
CVE-2026-23515
RCE - Command Injection in Signal K set-system-time plugin
8.8
CVE-2025-69203
Signal K Server Vulnerable to Access Request Spoofing