CVE-2026-35583
MEDIUMCVE-2026-35583 is a medium-severity (CVSS 5.3) Path Traversal vulnerability in gov.nsa.emissary:emissary. O3 Security confirms whether CVE-2026-35583 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Emissary has a Path Traversal via Blacklist Bypass in Configuration API
Blast Radius
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. Prior to 8.39.0, the configuration API endpoint (/api/configuration/{name}) validated configuration names using a blacklist approach that checked for , /, .., and trailing .. This could potentially be bypassed using URL-encoded variants, double-encoding, or Unicode normalization to achieve path traversal and read configuration files outside the intended directory. This vulnerability is fixed in 8.39.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | gov.nsa.emissary:emissary | all versions | 8.39.0 |
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 8.39.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-35583 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-2026-35583 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-2026-35583. 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-2026-35583 in your dependencies?
O3 detects CVE-2026-35583 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.