CVE-2026-39320

Signal K Server has an Unauthenticated Regular Expression Denial of Service (ReDoS) via WebSocket Subscription Paths

HIGH
7.5
CVSS Score
Published: April 21, 2026 at 12:07 AM UTC
Updated: October 26, 2026 at 10:10 PM UTC
1 product affected across 1 vendorSignal K Server

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Severity
HIGH7.5
Exploit prediction
EPSS 0.4%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.25.0
Affected range stops below 2.25.0, so it looks safe — our inference, not a vendor statement

References (4)

x_refsource_CONFIRMExploitVendor Advisory
Source: cverecord
https://github.com/SignalK/signalk-server/security/advisories/GHSA-7gcj-phff-2884
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/SignalK/signalk-server/pull/2568
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/SignalK/signalk-server/releases/tag/v2.25.0

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-400CWE-1333

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