CVE-2026-39320 | Signal K Server has an Unauthenticated Regular Expression Denial of Service (ReDoS) via WebSocket Subscription Paths

Exp

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.

Published: 2026-04-21 Last update: 2026-04-24 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-39320 is rated Exploit Available (57.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.43%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-39320

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-39320

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.05% 0.43% +0.38%
2 2026-04-27 0.04% 0.05% +0.01%
3 2026-04-21 — 0.04% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-39320

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-39320

GitHub Security Advisory for CVE-2026-39320

GHSA-7gcj-phff-2884 · Severity: high · Ecosystem: npm — Signal K Server has an Unauthenticated Regular Expression Denial of Service (ReDoS) via WebSocket Subscription Paths

Affected software / configurations for CVE-2026-39320

Vendor Product Version Raw CPE
signalk signal_k_server < 2.25.0 cpe:2.3:a:signalk:signal_k_server:*:*:*:*:*:*:*:*

References for CVE-2026-39320

cvelogic Threat Intelligence