CVE-2026-40242Published

Arcane Unauthenticated SSRF with Conditional Response Reflection in Template Fetch Endpoint

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-40242

Published

Arcane is an interface for managing Docker containers, images, networks, and volumes. Prior to 1.17.3, the /api/templates/fetch endpoint accepts a caller-supplied url parameter and performs a server-side HTTP GET request to that URL without authentication and without URL scheme or host validation. The server's response is returned directly to the caller. type. This constitutes an unauthenticated SSRF vulnerability affecting any publicly reachable Arcane instance. This vulnerability is fixed in 1.17.3.

Source published: 10 Apr 2026 20:34:12 UTC
Source modified: 13 Apr 2026 20:54:36 UTC
Observed here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 7.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

euvd · EUVD-2026-21599

Published

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Apr 10, 2026, 8:34:12 PM

dateUpdated: Apr 13, 2026, 8:54:36 PM

Source published: Apr 10, 2026, 8:34:12 PM (timezone not stated)
Source modified: Apr 13, 2026, 8:54:36 PM (timezone not stated)
Observed here: 28 Oct 2026 05:01:29 UTC
Source terms: ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 7.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

nvd · CVE-2026-40242

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Analyzed

Weakness classifications: CWE-918

Original publisher date fields

published: 2026-04-10T21:16:27.747

lastModified: 2026-10-26T21:10:00.170

1 source CPE criteria · context only

cpe:2.3:a:getarcane:arcane:*:*:*:*:*:*:*:*

The original JSON retains the logical configuration operators, exclusions and version bounds.

Source published: 10 Apr 2026 21:16:27 UTC
Source modified: 26 Oct 2026 21:10:00 UTC
Observed here: 27 Oct 2026 10:09:56 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 7.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

CVSS 3.1 · [email protected] · Primary · 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

osv · GHSA-ff24-4prj-gpmj

Published

### Summary The /api/templates/fetch endpoint accepts a caller-supplied url parameter and performs a server-side HTTP GET request to that URL without authentication and without URL scheme or host validation. The server's response is returned directly to the caller. type. This constitutes an unauthenticated SSRF vulnerability affecting any publicly reachable Arcane instance. ### Details - No allowlist or denylist of destination hosts/CIDRs - No requirement for the caller to be authenticated Response handling produces four distinct outcomes observable by the caller: - Valid JSON targets return a fully reflected response body if the returned fields fit the expected internal struct - Non-JSON HTTP 200 responses produce an error leaking the first byte of the response (`"Invalid JSON response: invalid character '<'..."`) - Non-200 responses leak the HTTP status code - TCP-level failures distinguish between closed ports (`"connection refused"`) and filtered ones (`"i/o timeout"`) ### PoC Send an unauthenticated GET request to `/api/templates/fetch`, passing the target URL as the `url` query parameter. <img width="1041" height="375" alt="image" src="https://github.com/user-attachments/assets/f9fd475e-90b0-4dec-95e1-0af6263f5bb5" /> ### Impact - Unauthenticated port scanning of internal networks - Access to internal HTTP services not exposed to the public internet (service discovery endpoints, internal dashboards, Kubernetes API)

Source published: 10 Apr 2026 20:59:27 UTC
Source modified: 21 Jul 2026 14:02:57 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Publisher rating · HIGH

osv · GO-2026-5356

Published

Arcane has Unauthenticated SSRF with Conditional Response Reflection in Template Fetch Endpoint in github.com/getarcaneapp/arcane/backend

Source published: 25 Jun 2026 18:43:19 UTC
Source modified: 25 Jun 2026 19:45:34 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.