CVE-2026-42455
LinkWarden: Stored XSS via Client-Side Archive Upload (Unsanitized HTML served from same origin)
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.
INFO
Published Date :
May 9, 2026, 12:16 a.m.
Last Modified :
July 24, 2026, 9:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-42455
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Sanitize JavaScript content from uploaded HTML files.
- Implement Content-Security-Policy header for archive access.
- Await and apply vendor patch when available.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-42455.
| URL | Resource |
|---|---|
| https://github.com/linkwarden/linkwarden/security/advisories/GHSA-fjvg-mch3-j3vg | |
| https://github.com/linkwarden/linkwarden/security/advisories/GHSA-fjvg-mch3-j3vg |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-42455 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-42455
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-42455 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-42455 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Jul. 24, 2026
Action Type Old Value New Value Added Translation Title: LinkWarden, Description: Linkwarden es un gestor de marcadores colaborativo, autohospedado y de código abierto para recopilar, organizar y archivar páginas web. En las versiones 2.14.0 y anteriores, el endpoint de carga de archivos (POST /API/v1/archives/[linkId]?format=4) acepta archivos HTML (text/html) sin sanear el contenido JavaScript. Cuando se accede posteriormente al archivo a través de GET /API/v1/archives/[linkId]?format=4, el HTML se sirve con Content-Type: text/html desde el origen de Linkwarden, sin ningún encabezado Content-Security-Policy. Esto permite la ejecución arbitraria de JavaScript en el contexto de la sesión autenticada de Linkwarden. En el momento de la publicación, no hay parches disponibles públicamente. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'linkwarden', 'product': 'linkwarden', 'versions': [{'status': 'affected', 'version': '<= 2.14.0'}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-42455', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-05-12T02:18:41.572672Z'} -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 12, 2026
Action Type Old Value New Value Added Reference https://github.com/linkwarden/linkwarden/security/advisories/GHSA-fjvg-mch3-j3vg -
New CVE Received by [email protected]
May. 09, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-79 Added Reference https://github.com/linkwarden/linkwarden/security/advisories/GHSA-fjvg-mch3-j3vg