Vulnerability details
CVE-2026-40470
Hackage package and doc upload stored XSS vulnerability
CVSS 3.1
9.9Critical
Official 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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 9.9Critical | 3.1 | CVEProject cvelistV5 (CNA) (redhat-cnalr) | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| No product information recorded. | |||
References and advisories
1
Kolun on Telegram @kolunsec
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Details
- Published
- 2026-04-23
- Last updated
- 2026-04-23
- State
- Published
- Assigner (CNA)
- redhat-cnalr
Exploit prediction (EPSS)
0.3%
Probability of exploitation in 30 days
23.8%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- No
- Exploitation
- None
- Technical impact
- Total
Weaknesses (CWE)
- CWE-79Improper neutralization of input during web page generation ('cross-site scripting')