CVE•Published 2026-05-18•Modified 2026-06-05•0 articles on news•7 live references•NVD data

CVE-2026-3471Mattermost · Mattermost_desktop

Vulnerability data via NVD (ingested)

CVSS v3.1

6.5

MEDIUM

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

EPSS percentile

Exploit Prediction Scoring System · top 88% of all CVEs

Weaknesses (CWE)

CWE-939Improper Authorization in Handler for Custom URL Scheme

Description

Mattermost Desktop App versions <=6.1 6.0.1 5.4.13.0 fail to prevent an invalid URL from loading in a pop-up window in the Mattermost Desktop App which allows a malicious server owner to repeated crash the application via calling {{window.open('javascript:alert()');}}. Mattermost Advisory ID: MMSA-2026-00618

Timeline

Published 2026-05-18

Modified 2026-06-05

External references

NVD MITRE Exploit-DB GitHub PoC Sploitus trickest/cve VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-3471

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Mattermost Mattermost Desktop"

All exposed Mattermost Mattermost Desktop instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Mattermost Desktop"

HTTP body or banner mentions "Mattermost Desktop" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-3471