Arcane Has a Command Injection in Arcane Updater Lifecycle Labels That Enables RCE

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

9.0 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

EPSS

• CVE-2026-23520: 1.85% estimated exploitation activity in the next 30 days; percentile 79.09 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Arcane’s updater service supported lifecycle labels com.getarcaneapp.arcane.lifecycle.pre-update and com.getarcaneapp.arcane.lifecycle.post-update that allowed defining a command to run before or after a container update. The label value is passed directly to /bin/sh -c without sanitization or validation. Because any authenticated user (not limited to administrators) can create projects through the API, an attacker can create a project that specifies one of these lifecycle labels with a malicious command. When an administrator later triggers a container update (either manually or via scheduled update checks), Arcane reads the lifecycle label and executes its value as a shell command inside the container. If the container is configured with host volume mounts in its Compose definition, the executed command may be able to read from or write to the host filesystem through the mounted paths. This can enable data theft and, in some configurations, escalation to full host…

Published by the source

15 Jan 2026, 20:10 UTC

Last modified by the source

15 Jan 2026, 22:33 UTC

Source last checked

26 Oct 2026, 15:14 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-gjqq-6r35-w3r8

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# Patch Next advisory brief: CVE-2026-23520

Advisory: Arcane Has a Command Injection in Arcane Updater Lifecycle Labels That Enables RCE
IDs: CVE-2026-23520, GHSA-gjqq-6r35-w3r8
Record: https://patchnext.com/advisories/cve-2026-23520 (revision 1, source checked 26 Oct 2026, 15:14 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/getarcaneapp/arcane/backend 0.0.0-20260114065515-5a9c2f92e11f. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/getarcaneapp/arcane/backend: affected < 0.0.0-20260114065515-5a9c2f92e11f; fixed in 0.0.0-20260114065515-5a9c2f92e11f

## Suggested inspection (read-only)
- Go github.com/getarcaneapp/arcane/backend: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/getarcaneapp/arcane/backend.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-gjqq-6r35-w3r8 (GitHub-reviewed advisory GHSA-gjqq-6r35-w3r8 lists affected ranges: Go github.com/getarcaneapp/arcane/backend >=0 <0.0.0-20260114065515-5a9c2f92e11f)

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