Emissary has a Path Traversal via Blacklist Bypass in Configuration API

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS

• CVE-2026-35583: 0.32% estimated exploitation activity in the next 30 days; percentile 25.09 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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. Details Vulnerable code — Configs.java (line 126) Weakness The blacklist blocked literal \, /, .., and trailing . but could potentially miss: - URL-encoded variants (%2e%2e%2f) if decoded after validation - Double-encoded sequences (%252e%252e%252f) - Unicode normalization bypasses - The approach relies on string matching rather than canonical path resolution Impact - Potential read access to configuration files outside the intended config directory - Information disclosure of sensitive configuration values Remediation Fixed in PR #1292, merged into release 8.39.0. The blacklist was replaced with an allowlist regex that only…

Published by the source

8 Apr 2026, 00:12 UTC

Last modified by the source

8 Apr 2026, 00:12 UTC

Source last checked

26 Oct 2026, 16:45 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-hxf2-gm22-7vcm

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# Patch Next advisory brief: CVE-2026-35583

Advisory: Emissary has a Path Traversal via Blacklist Bypass in Configuration API
IDs: CVE-2026-35583, GHSA-hxf2-gm22-7vcm
Record: https://patchnext.com/advisories/cve-2026-35583 (revision 1, source checked 26 Oct 2026, 16:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: gov.nsa.emissary:emissary 8.39.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven gov.nsa.emissary:emissary: affected < 8.39.0; fixed in 8.39.0

## Suggested inspection (read-only)
- Maven gov.nsa.emissary:emissary: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on gov.nsa.emissary:emissary.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-hxf2-gm22-7vcm (GitHub-reviewed advisory GHSA-hxf2-gm22-7vcm lists affected ranges: Maven gov.nsa.emissary:emissary >=0 <8.39.0)

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