CVE-2026-42461 Arcane Vulnerable to Unauthenticated Disclosure of Custom Compose Template Content (incl. `.env` secrets)
Unauthenticated attackers can read sensitive environment variables and secrets from custom Docker Compose templates due to missing authorization on API endpoints.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42461?
CVE-2026-42461 is a high-severity missing authorization vulnerability in getarcaneapp arcane, published on 9 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Arcane is an interface for managing Docker containers, images, networks, and volumes. Prior to version 1.18.0, four GET endpoints under /api/templates* in Arcane's Huma backend are registered without any Security requirement, allowing any unauthenticated network client to list and read the full Compose YAML and .env content of every custom template stored in the instance. Because Arcane's UI exposes a "Save as Template" flow on the project / swarm-stack creation pages that persists the operator's real env content (database passwords, API keys, etc.) verbatim, this missing authorization is an unauthenticated read of operator secrets in practice — not a theoretical info-disclosure. The frontend explicitly treats /customize/templates/* as an authenticated area (PROTECTED_PREFIXES in frontend/src/lib/utils/redirect.util.ts), and every CRUD operation (POST/PUT/DELETE) on the same paths requires a Bearer/API key, so this is a clear backend authorization gap, not intended public access. This issue has been patched in version 1.18.0.
Weakness: CWE-862
Which versions are affected by CVE-2026-42461?
3 open source packages ship an affected version, including github.com/getarcaneapp/arcane/backend. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/getarcaneapp/arcane/backend Go | All versions | 1.18.0 |
github.com/getarcaneapp/arcane/backend Go | All versions | 1.18.0 |
github.com/getarcaneapp/arcane/backend Go | All versions | 1.18.0 |
Products include Getarcane Arcane.
How do I fix CVE-2026-42461?
Upgrade github.com/getarcaneapp/arcane/backend to 1.18.0 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-42461 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42461 exists.
Public exploit code: 1 Nuclei template.
Other vulnerabilities in getarcaneapp arcane
Sources
Also known as GHSA-cxx3-hr75-4q96, GO-2026-5340.