How severe is CVE-2026-4039?

CVE-2026-4039 has a CVSS score of 8.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-4039?

CVE-2026-4039 affects the following packages: openclaw (npm). Ecosystems affected: npm.

How do I fix CVE-2026-4039?

Update openclaw to 2026.2.21 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-4039 is resolved across your whole dependency graph.

How do I detect CVE-2026-4039 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openclaw. 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-2026-4039 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-2026-4039?

O3 pinpoints whether CVE-2026-4039 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-2026-4039 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-4039 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-4039?

CVE-2026-4039 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 23th 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 indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-4039?

CVE-2026-4039 is classified as CWE-74 (CWE-74), Code Injection (CWE-94). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-4039 published, and has it been updated?

CVE-2026-4039 was published on March 12, 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-2026-4039: openclaw Remote Code Execution (High 8.8)

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk23th percentile+0.20%

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

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

openclawnpm

4.4Mdownloads / week

Description

A vulnerability was determined in OpenClaw 2026.2.19-2. This vulnerability affects the function applySkillConfigenvOverrides of the component Skill Env Handler. Executing a manipulation can lead to code injection. It is possible to launch the attack remotely. Upgrading to version 2026.2.21-beta.1 is able to resolve this issue. This patch is called 8c9f35cdb51692b650ddf05b259ccdd75cc9a83c. It is recommended to upgrade the affected component.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`openclaw`	all versions	2026.2.21

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openclaw. 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 openclaw to 2026.2.21 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-4039 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-2026-4039 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-2026-4039. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

A vulnerability was determined in OpenClaw 2026.2.19-2. This vulnerability affects the function applySkillConfigenvOverrides of the component Skill Env Handler. Executing a manipulation can lead to code injection. It is possible to launch the attack remotely. Upgrading to version 2026.2.21-beta.1 is able to resolve this issue. This patch is called 8c9f35cdb51692b650ddf05b259ccdd75cc9a83c. It is recommended to upgrade the affected component.

O3 Security · Impact-Aware SCA

Is CVE-2026-4039 in your dependencies?

O3 detects CVE-2026-4039 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-2026-4039