NationalSecurityAgency/emissary has an incomplete fix for CVE-2026-35571

Exploitation

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

CVSS

4.8 · CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary The URL validation regex `^(https?:/)?/.*` added to emissary's `NavAction.java` allows protocol-relative URLs (`//evil.com/...`) and single-slash scheme variants (`http:/evil.com`) to bypass validation, enabling SSRF and open redirect attacks.

Affected Package - Ecosystem: Maven - Package: NationalSecurityAgency/emissary - Affected versions: = e2078417464b

Severity Medium

CWE CWE-918 — Server-Side Request Forgery (SSRF)

Details The fix in `NavAction.java` (line 47) introduces a `VALID_LINK` pattern: ```java Pattern.compile("^(https?:/)?/.*") ``` This regex is intended to restrict navigation links to relative paths and HTTP/HTTPS URLs. However, it has multiple bypass vectors. Protocol-relative URLs (`//evil.com/...`): The group `(https?:/)?` is optional, so the pattern reduces to `//.*` when the group is absent. This matches `//evil.com/steal?c=SESSION`, which browsers resolve to the current page's protocol plus the attacker's host. Single-slash…

Published by the source

30 Oct 2026, 22:51 UTC

Last modified by the source

30 Oct 2026, 23:00 UTC

Source last checked

31 Oct 2026, 07:05 UTC

1. Revision 2 · amended · 31 Oct 2026

   Amended from osv record GHSA-c6q7-wqw2-h65w

2. Revision 1 · created · 30 Oct 2026

   Published from ghsa record GHSA-c6q7-wqw2-h65w

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# Patch Next advisory brief: CVE-2026-54442

Advisory: NationalSecurityAgency/emissary has an incomplete fix for CVE-2026-35571
IDs: CVE-2026-54442, GHSA-c6q7-wqw2-h65w
Record: https://patchnext.com/advisories/cve-2026-54442 (revision 2, source checked 31 Oct 2026, 07:05 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.8)
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 8.51.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven gov.nsa.emissary:emissary: affected < 8.51.0; fixed in 8.51.0

## 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-c6q7-wqw2-h65w (GitHub-reviewed advisory GHSA-c6q7-wqw2-h65w lists affected ranges: Maven gov.nsa.emissary:emissary >=0 <8.51.0)
- Verified: https://osv.dev/vulnerability/GHSA-c6q7-wqw2-h65w (OSV record GHSA-c6q7-wqw2-h65w lists affected ranges: Maven gov.nsa.emissary:emissary >=0 <8.51.0 (fixed))

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