How severe is CVE-2026-34156?

CVE-2026-34156 has a CVSS score of 9.9/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-34156?

CVE-2026-34156 affects the following packages: @nocobase/plugin-workflow-javascript (npm). Ecosystems affected: npm.

How do I fix CVE-2026-34156?

Update @nocobase/plugin-workflow-javascript to 2.0.28 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34156 is resolved across your whole dependency graph.

How do I detect CVE-2026-34156 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @nocobase/plugin-workflow-javascript. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-34156 if there is no patch (or I can't update yet)?

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 does O3 Security protect against CVE-2026-34156?

O3 pinpoints whether CVE-2026-34156 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-34156 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2026-34156, including 1 documented proof-of-concept exploit on Exploit-DB. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2026-34156?

CVE-2026-34156 has an EPSS (Exploit Prediction Scoring System) score of 36.5%, placing it in the 98th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score warrants monitoring and prompt remediation.

What type of vulnerability is CVE-2026-34156?

CVE-2026-34156 is classified as CWE-913 (CWE-913). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2026-34156?

A Nuclei detection template exists for CVE-2026-34156, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2026-34156 published, and has it been updated?

CVE-2026-34156 was published on March 31, 2026 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-34156: @nocobase/plugin-workflow… Remote Code Executio…

EPSS Exploitation Probability

via FIRST.org ↗

36.5%probability of exploitation in next 30 days

Moderate Risk98th percentile+7.00%

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.

Blast Radius

1 pkg affected

📦@nocobase/plugin-workflow-javascript

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.

Description

NocoBase is an AI-powered no-code/low-code platform for building business applications and enterprise solutions. Prior to version 2.0.28, NocoBase's Workflow Script Node executes user-supplied JavaScript inside a Node.js vm sandbox with a custom require allowlist (controlled by WORKFLOW_SCRIPT_MODULES env var). However, the console object passed into the sandbox context exposes host-realm WritableWorkerStdio stream objects via console._stdout and console._stderr. An authenticated attacker can traverse the prototype chain to escape the sandbox and achieve Remote Code Execution as root. This issue has been patched in version 2.0.28.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@nocobase/plugin-workflow-javascript`	all versions	2.0.28

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @nocobase/plugin-workflow-javascript. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @nocobase/plugin-workflow-javascript to 2.0.28 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34156 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 pinpoints whether CVE-2026-34156 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-34156. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

NocoBase is an AI-powered no-code/low-code platform for building business applications and enterprise solutions. Prior to version 2.0.28, NocoBase's Workflow Script Node executes user-supplied JavaScript inside a Node.js vm sandbox with a custom require allowlist (controlled by WORKFLOW_SCRIPT_MODULES env var). However, the console object passed into the sandbox context exposes host-realm WritableWorkerStdio stream objects via console._stdout and console._stderr. An authenticated attacker can traverse the prototype chain to escape the sandbox and achieve Remote Code Execution as root. This iss

O3 Security · Impact-Aware SCA

Is CVE-2026-34156 in your dependencies?

O3 detects CVE-2026-34156 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works

CVE-2026-34156