Cloudanix VulnDB

CVE-2026-40470

Critical · 9.9

CVSS

9.9

EPSS

0.4%

Published

Apr 23, 2026

CISA due date

—

The record

A critical XSS vulnerability affected hackage-server and hackage.haskell.org. HTML and JavaScript files provided in source packages or via the documentation upload facility were served as-is on the main hackage.haskell.org domain. As a consequence, when a user with latent HTTP credentials browses to the package pages or documentation uploaded by a malicious package maintainer, their session can be hijacked to upload packages or documentation, amend maintainers or other package metadata, or perform any other action the user is authorised to do.

Affected packages

Ecosystem Package Introduced Fixed

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