CVE-2026-40471Network attack vector

Unauthorized actions via missing cross-site request checks

Published Apr 23, 2026 · Updated Apr 23, 2026

Cross-site request forgery in Haskell.org hackage-server 0.1 and later allows remote attackers to perform actions through a victim's browser. The request pipeline dispatched state-changing requests without validating origin signals or requiring a CSRF token, so foreign-site scripts inherited browser credentials. Exploitation requires a user to visit attacker-controlled content while latent credentials are available, enabling package uploads or administrative actions; unauthenticated account registration can also be forged.

CVSS severity9.6
Critical
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site request forgery in Haskell.org hackage-server 0.1 and later allows remote attackers to perform actions through a victim's browser. The request pipeline dispatched state-changing requests without validating origin signals or requiring a CSRF token, so foreign-site scripts inherited browser credentials. Exploitation requires a user to visit attacker-controlled content while latent credentials are available, enabling package uploads or administrative actions; unauthenticated account registration can also be forged.

The record

CVE
CVE-2026-40471
Published
Apr 23, 2026
Updated
Apr 23, 2026
Vendor
Haskell.org
Product
hackage-server
Classifications
CWE-352, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.1 <*

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Haskell.org · hackage-serverversion=0.1 <*

Published CVSS scores

9.6redhat-cnalrCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-352Cross-Site Request Forgery (CSRF)
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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