CVE-2026-23520 is a critical-severity (CVSS 9) OS Command Injection vulnerability in github.com/getarcaneapp/arcane/backend. A fix is available for github.com/getarcaneapp/arcane/backend — see the affected versions and patch details below.
Arcane has a Command Injection in Arcane Updater Lifecycle Labels Enables RCE
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-23520.
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.
How urgent is this, really
CVE-2026-23520 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/getarcaneapp/arcane/backendReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
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 compromise (for example, if /var/run/docker.sock is mounted).
Impact
- Remote code execution (RCE) within the updated container context.
- Host filesystem access when host volumes are mounted into the container.
- Potential data exfiltration via outbound network requests or by exposing readable files.
- Potential full host compromise if sensitive mounts are present (e.g., /var/run/docker.sock).
Patches
The lifecycle labels com.getarcaneapp.arcane.lifecycle.pre-update and com.getarcaneapp.arcane.lifecycle.post-update have been removed to eliminate this attack surface.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/getarcaneapp/arcane/backend | all versions | 0.0.0-20260114065515-5a9c2f92e11fgo get github.com/getarcaneapp/arcane/backend@v0.0.0-20260114065515-5a9c2f92e11f |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/getarcaneapp/arcane/backend, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/getarcaneapp/arcane/backend to 0.0.0-20260114065515-5a9c2f92e11f or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-23520 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-23520 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-23520. 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-2026-23520 in your dependencies?
O3 Security finds CVE-2026-23520 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.