CVE-2026-40242Public exploitNetwork attack vector

Unauthenticated internal service access via unchecked template URL

Published Apr 10, 2026 · Updated Apr 10, 2026

SSRF in Arcane before 1.17.3 allows remote attackers to reach internal HTTP services through the template-fetch API. The unauthenticated /api/templates/fetch endpoint passes its url parameter to a server-side HTTP GET without validating the scheme, host, or destination address and reflects compatible JSON bodies. Any network client that can reach an Arcane instance can enumerate internal ports from response differences and read responses that match the expected template structure.

CVSS severity7.2
High
EPSS probability0.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

SSRF in Arcane before 1.17.3 allows remote attackers to reach internal HTTP services through the template-fetch API. The unauthenticated /api/templates/fetch endpoint passes its url parameter to a server-side HTTP GET without validating the scheme, host, or destination address and reflects compatible JSON bodies. Any network client that can reach an Arcane instance can enumerate internal ports from response differences and read responses that match the expected template structure.

The record

CVE
CVE-2026-40242
Published
Apr 10, 2026
Updated
Apr 10, 2026
Vendor
Arcane
Product
Arcane
Classifications
CWE-918, T1046, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.17.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Arcane · Arcaneversion=< 1.17.3

Published CVSS scores

7.2GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1046Network Service Discovery
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo