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.
History

Tue, 28 Apr 2026 09:45:00 +0000

Type Values Removed Values Added
First Time appeared Hackage-server
Hackage-server hackage-server
Vendors & Products Hackage-server
Hackage-server hackage-server

Thu, 23 Apr 2026 18:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Thu, 23 Apr 2026 15:45:00 +0000

Type Values Removed Values Added
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.
Title Hackage package and doc upload stored XSS vulnerability
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 9.9, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L'}


cve-icon MITRE

Status: PUBLISHED

Assigner: redhat-cnalr

Published:

Updated: 2026-04-23T16:22:27.341Z

Reserved: 2026-04-13T15:23:17.067Z

Link: CVE-2026-40470

cve-icon Vulnrichment

Updated: 2026-04-23T16:19:49.844Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-04-23T16:16:25.523

Modified: 2026-04-24T14:41:55.890

Link: CVE-2026-40470

cve-icon Redhat

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