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Vulnerabilities

Vulnerability · CVE-2026-40471

Hackage CSRF vulnerability

Published Mar 28, 2026 · catalog updated Jun 17, 2026 · Hackage CSRF

Check if you run it

No confirmed exploitation is on record for CVE-2026-40471. EPSS is 0.18%. Act only if a listed version of Hackage CSRF is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Hackage CSRF).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Critical9.6
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.18%
Remediation
Not established
Affected products
Hackage hackage-server

# Hackage CSRF vulnerability * Vulnerable File: (example) * Impact: can forge requests through XSS 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). To fix the issue, a new CSRF middleware checks all requests. Requests using HTTP methods other than , and are subject to a check of the [ header][sec-fetch-site], which is [widely supported by modern browsers][caniuse-sec-fetch-site]. Cross-site requests are . Certain approved and expected non-browser user agents (e.g. ) are exempted from the check, as are requests using token authentication ( ). The fix has been [committed][commit] and deployed on . ## Acknowledgements - **Joshua Rogers** (https://joshua.hu/) of AISLE (https://aisle.com/) reported the issue to the Haskell Security Response Team. - **Spenser Janssen** implemented the fix, and **Fraser Tweedale** reviewed it. - **Gershom Bazerman** merged the fix and deployed it to . [sec-fetch-site]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Sec-Fetch-Site [caniuse-sec-fetch-site]: https://caniuse.com/?search=sec-fetch-site [commit]: https://github.com/haskell/hackage-server/commit/2de3ae45082f8f3f29a41f6aff620d09d0e74058

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Hackage hackage-server0.4, 0.5.0
  • Hackage hackage-serverfrom 0.1

How to fix CVE-2026-40471

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-40471. EPSS is 0.18%. Act only if a listed version of Hackage CSRF is installed.

Which versions are affected?

Compare what you have installed with 0.4, 0.5.0, from 0.1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-352: Cross-Site Request Forgery (CSRF). EPSS 0.18%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 28, 2026 · OpenSSF OSV / OSV Scanner

    Detected

    # Hackage CSRF vulnerability * Vulnerable File: (example) * Impact: can forge requests through XSS 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

  2. Apr 14, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    # Hackage CSRF vulnerability * Vulnerable File: (example) * Impact: can forge requests through XSS 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

  3. Jun 17, 2026 · NIST NVD

    Updated

    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).

Sources

  • CVE.orgVulnerability recordCVE-2026-40471

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-40471

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-40471

    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

    nvd.nist.gov
  • OpenSSF OSV / OSV ScannerPackage advisoryHSEC-2026-0002

    Hackage CSRF vulnerability

    osv.dev

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.