Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-40470

Severity CVSS v4.0:
Pending analysis
Type:
CWE-79 Cross-Site Scripting (XSS)
Publication date:
23/04/2026
Last modified:
24/04/2026

Description

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

Impact

Vector 3.x
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L CVSS v3.1 Severity and Metrics:

Base Score: 9.90 CRITICAL
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Changed
Confidentiality (C): High
Integrity (I): High
Availability (A): Low

Base Score 3.x
9.90
Severity 3.x
CRITICAL

References to Advisories, Solutions, and Tools