External risk intelligence

Attacker can take control of Hackage server and publish malicious code due to missing security checks.

CVE advisorySeverity: CRITICAL (CVSS 9.6)

CVE-2026-40471

Malicious websites can hijack your browser to upload fake code or create accounts on the Hackage package server, potentially compromising your software supply chain. This affects an internet-facing platform used for public software distribution.

5Halo Surface Signal

Cross-site Request Forgery

External exposure likelihood

Halo Surface Signal score for CVE-2026-40471

Hackage-server is a centralized, internet-accessible package management platform designed for public software distribution. Its web interface and API endpoints are inherently exposed to the public internet by design to facilitate global developer access.

PCI scan relevance

PCI Relevance for CVE-2026-40471

Yes

CVE-2026-40471 — Halo PCI Relevance: Yes. Under typical PCI ASV external scan criteria, this issue may be flagged for scan prioritization.

This CVE is PCI scan-relevant because it involves cross-site request forgery (CSRF) that can lead to unauthorized package uploads or administrative actions on hackage-server.

Scan-prioritization guidance only—not a PCI DSS certification or ASV attestation.

Horizon Alert

Summary of the vulnerability and why it matters

This issue affects hackage-server, a platform for managing software packages. The absence of cross-site request forgery (CSRF) protection means that malicious websites can trick users into performing unintended actions on the hackage-server, potentially leading to unauthorized package uploads or account creation.

  • Sensitive actions can be performed.
  • Unauthenticated users can be affected.
  • The server is reachable from the internet.

Attack Path

How an attacker could exploit the issue

An attacker can exploit this vulnerability by tricking a logged-in user into visiting a malicious website, which then forces their browser to send requests to the hackage server. This allows the attacker to perform actions on behalf of the user, such as uploading malicious packages or creating new accounts.

  • No authentication required for some actions.
  • Exploits user's existing session.
  • Targets web interface endpoints.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability in hackage-server allows attackers to exploit CSRF to potentially upload packages or abuse administrative actions. While unauthenticated actions like creating user accounts can also be abused, the primary concern is the ability to execute actions with latent credentials.

  • Exploitation requires user interaction.
  • Public exploit code is not available.
  • No KEV signal detected.

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

Prioritize blocking all unexpected inbound traffic to hackage-server and immediately investigate logs for any signs of unauthorized package uploads or account creations, as this vulnerability allows unauthenticated users to perform administrative actions. Because a reliable exploit is not detailed, focus on containment and detection until a patch is available.

  • Block foreign site requests.
  • Monitor for account creation and package uploads.
  • If impacted, isolate or take services offline.

Frequently asked questions

What is hackage-server and what is it used for?

Hackage-server is a platform used for managing software packages. It serves as a central hub for developers to distribute and access code libraries and other software components, facilitating the broader software development ecosystem.

What type of vulnerability is CVE-2026-40471 in hackage-server?

CVE-2026-40471 is a Cross-Site Request Forgery (CSRF) vulnerability. This weakness means that malicious websites can trick users' browsers into sending unintended requests to the hackage-server, potentially allowing unauthorized actions.

How can an attacker exploit this CSRF vulnerability on hackage-server?

An attacker can exploit this by luring a logged-in user to a malicious website. This site then prompts the user's browser to send requests to hackage-server, enabling the attacker to perform actions as if they were the legitimate user, such as uploading packages. Actions by unauthenticated users are also possible.

Who should be concerned about CVE-2026-40471 in hackage-server?

Organizations running hackage-server should be concerned. Because hackage-server is designed for public software distribution and is internet-accessible, it is exposed to potential exploitation by external attackers. [cite: halo]

What are the first steps for those running hackage-server?

As a first step, administrators should investigate logs for any suspicious activity, such as unauthorized package uploads or new user account creations. It is also advisable to block unexpected inbound traffic to the hackage-server until a patch becomes available.

References