# CVE-2026-40471: Hackage CSRF vulnerability

> Attackers can trick users into performing unauthorized actions like uploading packages or creating accounts on the Hackage server.

- **Severity:** Critical 9.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 23 Apr 2026
- **Updated:** 23 Apr 2026
- **Also known as:** GHSA-mf84-vmqg-86fm, HSEC-2026-0002

## What is CVE-2026-40471?

CVE-2026-40471 is a critical vulnerability in hackage-server, published on 23 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

hackage-server lacked Cross-Site Request Forgery (CSRF) protection across its endpoints. Scripts on foreign sites could trigger requests to hackage server, possibly abusing latent credentials to upload packages or perform other administrative actions. Some unauthenticated actions could also be abused (e.g. creating new user accounts).

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2026-40471?

1 open source package ship an affected version, including hackage-server.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `hackage-server` | Hackage | From 0.1 | None |

## How do I fix CVE-2026-40471?

No fix has been published for CVE-2026-40471 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-40471 being exploited?

There is no known exploitation of CVE-2026-40471 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40471 and fix it if it is affected.

What it is: CVE-2026-40471 is a critical vulnerability in hackage-server, published on 23 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-40471 in the wild and no public exploit code.

Affected packages and fixed versions:
- hackage-server (Hackage): affected from 0.1; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-40471/ (Markdown: https://insights.sbomify.com/CVE-2026-40471/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40471
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40471
- OSV: https://osv.dev/vulnerability/CVE-2026-40471

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40471/
Summaries are generated and may contain mistakes; the official description above is the record.