CVE-2026-42455 HIGH

CVE-2026-42455: LinkWarden: Stored XSS via Client-Side Archive Upload (Unsanitized HTML served from same origin)

Vendor Linkwarden
Product linkwarden
Weakness CWE-79 · XSS
Published May 8, 2026
Last update May 12, 2026

CVSS base score

8.8/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

01Description

Linkwarden is a self-hosted, open-source collaborative bookmark manager to collect, organize and archive webpages. In versions 2.14.0 and prior, the archive upload endpoint (POST /api/v1/archives/[linkId]?format=4) accepts HTML files (text/html) without sanitizing JavaScript content. When the archive is later accessed via GET /api/v1/archives/[linkId]?format=4, the HTML is served with Content-Type: text/html from the Linkwarden origin, without any Content-Security-Policy header. This allows arbitrary JavaScript execution in the context of the authenticated Linkwarden sessio. At time of publication, there are no publicly available patches.

Key dates

02Disclosure timeline

May 8, 2026 CVE published
May 12, 2026 Record updated