CVE-2026-35582 is a high-severity (CVSS 8.8) remote code execution vulnerability in gov.nsa.emissary:emissary. O3 Security confirms whether CVE-2026-35582 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Emissary has an OS Command Injection via Unvalidated IN_FILE_ENDING / OUT_FILE_ENDING in Executrix
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.
Real-World Exposure
gov.nsa.emissary:emissaryReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Emissary is a P2P based data-driven workflow engine. In versions 8.42.0 and below, Executrix.getCommand() is vulnerable to OS command injection because it interpolates temporary file paths into a /bin/sh -c shell command string without any escaping or input validation. The IN_FILE_ENDING and OUT_FILE_ENDING configuration keys flow directly into these paths, allowing a place author who can write or modify a .cfg file to inject arbitrary shell metacharacters that execute OS commands in the JVM process's security context. The framework already sanitizes placeName via an allowlist before embedding it in the same shell string, but applies no equivalent sanitization to file ending values. No runtime privileges beyond place configuration authorship, and no API or network access, are required to exploit this vulnerability. This is a framework-level defect with no safe mitigation available to downstream implementors, as Executrix provides neither escaping nor documented preconditions against metacharacters in file ending inputs. This issue has been fixed in version 8.43.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | gov.nsa.emissary:emissary | all versions | 8.43.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for gov.nsa.emissary:emissary. 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 gov.nsa.emissary:emissary to 8.43.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-35582 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-2026-35582 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-2026-35582. 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-2026-35582 in your dependencies?
O3 detects CVE-2026-35582 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.