What is CVE-2026-35571?

CVE-2026-35571 is a medium-severity vulnerability in Nationalsecurityagency Emissary, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2026-04-07.

How severe is CVE-2026-35571?

Medium severity. CVSS v3 base score is 4.8 out of 10.

XSS in Nationalsecurityagency Emissary

CVE-2026-35571

Emissary is a P2P based data-driven workflow engine. Prior to 8.39.0, Mustache navigation templates interpolated configuration-controlled link values directly into href attributes without URL scheme validation. An administrator who could modify the navItems configuration could inject javascript: URIs, enabling stored cross-site scripting (XSS) against other authenticated users viewing the Emissary web interface. This vulnerability is fixed in 8.39.0.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-04-07 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (16.3th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 16.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

Nationalsecurityagency Emissary — versions < 8.39.0
Nsa Emissary

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/NationalSecurityAgency/emissary/security/advisories/GHSA-cpm7-cfpx-3… (Exploit, Third Party Advisory, Mitigation)
github.com/NationalSecurityAgency/emissary/pull/1293 (Patch)

Frequently asked questions

What is CVE-2026-35571?: CVE-2026-35571 is a medium-severity vulnerability in Nationalsecurityagency Emissary, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2026-04-07.
How severe is CVE-2026-35571?: Medium severity. CVSS v3 base score is 4.8 out of 10.