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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.

PUBLISHED Reserved 2026-04-13 | Published 2026-04-23 | Updated 2026-04-23 | Assigner redhat-cnalr




CRITICAL: 9.9CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

Problem types

CWE-79 Improper neutralization of input during web page generation ('cross-site scripting')

Product status

Default status
unaffected

0.1 (semver) before 0.6
affected

References

osv.dev/vulnerability/HSEC-2024-0004

cve.org (CVE-2026-40470)

nvd.nist.gov (CVE-2026-40470)

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