CVE-2026-42455CWE-79

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

High · published May 8, 2026

CVSS v4.0
8.8
EPSS
1%
Percentile
45.3
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.8 · HIGH
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
EPSS
0.00551 · 45.3th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-05-08T23:10Z
EPSS history
Timeline
  • 08 MAY 23:10Z
    LinkWarden: Stored XSS via Client-Side Archive Upload (Unsanitized HTML served from same origin)
    cvelistv5