CVE•Published 2026-05-15•Modified 2026-05-18•0 articles on news•5 live references•NVD data
CVE-2026-4054Mattermost · Mattermost_server
Vulnerability data via NVD (ingested)
CVSS v3.1
4.3
MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
EPSS percentile
—
Weaknesses (CWE)
Description
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 Fail to validate the response body of proxied images, which allows a remote attacker to enact client-side DoS via an SVG file served from an attacker-controlled origin under a non-SVG Content-Type header (e.g. image/png) embedded in an og:image meta tag or Markdown image link.. Mattermost Advisory ID: MMSA-2026-00630
Timeline
Published 2026-05-15
Modified 2026-05-18
External references
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-2026-4054Hosts Shodan has explicitly fingerprinted as vulnerable.
Shodan · product
product:"Mattermost Mattermost Server"All exposed Mattermost Mattermost Server instances — cross-reference with the CVE's affected-version range.
Shodan · banner/body mention
http.html:"Mattermost Server"HTTP body or banner mentions "Mattermost Server" — catches deploys Shodan didn't identify as a product.
More intel sources (5)
Shodan report
vuln:CVE-2026-4054Country / ASN / product breakdown for the vuln query.
Censys
vulnerabilities.cve_id: CVE-2026-4054Censys host search filtered to this CVE id.
grep.app
CVE-2026-4054Public source-code mentions — fast PoC discovery.
GitHub code
CVE-2026-4054GitHub code search for direct mentions.
Google dork
"CVE-2026-4054" exploit -site:nvd.nist.govWrite-ups and news, NVD excluded.
Known PoCs on GitHub (4)
We haven't classified any articles referencing CVE-2026-4054 yet. The external references above still apply.