CVE-2026-56681

HIGH

7.3

CVSS v3

Description

9Router is an AI router & token saver. Prior to 0.5.6, 9Router deployments that allow requests to reach Next.js without the sanitizing custom-server.js wrapper trust the client-supplied X-9r-Real-Ip header in src/dashboardGuard.js when isLocalRequest decides whether canAccessPublicLlmApi may skip API-key validation for /api/v1/* routes. A remote unauthenticated attacker can set X-9r-Real-Ip to 127.0.0.1 and be classified as a local client, including on the verified GET /api/v1/models route. This permits unauthorized use of the instance owner's configured LLM providers, consumption of paid credits, and enumeration of configured providers and models. This issue is fixed in version 0.5.6.

CWE-807

How to fix

Remediation Available

9routernpm

Fixed in:0.5.8GHSA-5mj8-gf6m-fhw8

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityLow

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Exploit Intelligence

0.97%probability of exploitation in 30 days

61stpercentile

Moderate risk: more likely to be exploited than 61% of all known CVEs.

References

Other references3

Related Vulnerabilities

Other CWE-807 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2026-21509	High	7.8	71%	KEV	Fix
CVE-2024-13974	High	8.1	7.4%	-	Fix
CVE-2026-34486	High	7.5	6.6%	KEV	Fix
CVE-2021-41129	High	8.1	1.8%	-	Fix
CVE-2026-21514	High	7.8	1.6%	KEV	-
CVE-2025-49827	Critical	9.8	1.4%	-	Fix

Common questions

How do I fix CVE-2026-56681?

Upgrade 9router to 0.5.8 or later.

Is CVE-2026-56681 being actively exploited?

Not that we know of. CVE-2026-56681 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.97% is the estimated probability that it will be exploited in the next 30 days. That is higher than 61% of all scored CVEs.

How severe is CVE-2026-56681?

CVE-2026-56681 has a CVSS v3 base score of 7.3, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-56681 affect?

Published advisories record a fix for 9router (npm). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-28.