VULNERABILITY INTELLIGENCE
CVE-2026-40470
CVSS score9.9 CRITICAL
EPSS probability0.31%
CISA KEVNot currently listed
Published2026-04-23
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L
Description
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.
Weakness classification
- 74b3a70d-cca6-4d34-9789-e83b222ae3be: CWE-79