CVE-2026-40470

critical · 9.9

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.

9.9

CVSS

0.3%

EPSS (exploit prob.)

24th

EPSS percentile

2026-04-23

Published

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

Weaknesses

CWE-79

References

https://osv.dev/vulnerability/HSEC-2024-0004

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-40470