CVE-2026-42461
HIGHArcane 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…
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
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.
Affected Products
arcanegetarcaneDetection & mitigation playbook
Vendor / applianceDetect
Inventory every getarcane arcane deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Fix
Apply the getarcane arcane security patch or hotfix for CVE-2026-42461 on the affected version, following the vendor advisory for your exact build.
Workarounds
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2026-42461 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.
Tailored to CVE-2026-42461. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-42461 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2026-42461 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.