CVE-2026-40242
MediumExploitedPublic exploitArcane has Unauthenticated SSRF with Conditional Response Reflection in Template Fetch Endpoint
Published Apr 10, 2026 · Updated Aug 12, 2026 · Also known as GHSA-ff24-4prj-gpmj, GO-2026-5356
Key Facts
Patch immediately- CVE-2026-40242 is a medium-severity vulnerability (CVSS 6.5 v3.1) affecting Arcane (Getarcane), github.com/getarcaneapp/arcane/backend (go).
- It is exploited in the wild, listed in Industry KEV feed, CIRCL KEV since Sep 17, 2026. Public exploit code is available.
- EPSS estimates a 0.7% probability of exploitation in the next 30 days.
- Fixed versions are available, including Arcane 1.17.3, github.com/getarcaneapp/arcane/backend 1.17.3.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS (30-day exploit likelihood)
0.7%
Higher than 53.0% of all scored CVEs
Exploited in the wild
Yes
2 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2026-40242 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Sep 17, 2026 | n/a | Not reported |
| CIRCL KEV | Sep 17, 2026 | n/a | Not reported |
Required action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Affected Products
3 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| ArcaneGetarcane | >= < 1.17.3 | 1.17.3 |
| github.com/getarcaneapp/arcane/backendgo | See advisory | 1.17.3 |
Patched Releases
Arcane
1.17.3
github.com/getarcaneapp/arcane/backend
1.17.3
Timeline
Publicly disclosed
Apr 10, 2026
Last updated
Aug 12, 2026
Added to Industry KEV feed
Sep 17, 2026
Added to CIRCL KEV
Sep 17, 2026
Weakness Type
- CWE-918 Server-Side Request Forgery (SSRF)
References
- advisoryGHSA advisory
- advisorycve.org · CVERecord
- advisorynvd.nist.gov · CVE-2026-40242
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
FAQ
Common Questions.
Arcane is an interface for managing Docker containers, images, networks, and volumes.
Affected: Arcane (Getarcane) versions >= < 1.17.3; github.com/getarcaneapp/arcane/backend (go). The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed, CIRCL KEV since Sep 17, 2026.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including Arcane 1.17.3, github.com/getarcaneapp/arcane/backend 1.17.3.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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