CVE-2026-42455

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

HIGH
8.8
CVSS Score
Published: May 8, 2026 at 11:10 PM UTC
Updated: July 24, 2026 at 09:20 PM UTC
1 product affected across 1 vendorLinkwarden

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Severity
HIGH8.8
Exploit prediction
EPSS 0.5%
SSVC
PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.8HIGHGitHub_M
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-79

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