How severe is CVE-2026-40472?

CVE-2026-40472 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.

Is CVE-2026-40472 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-40472?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-40472 have an EU (EUVD) identifier?

Yes. CVE-2026-40472 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-25235.

When was CVE-2026-40472 published?

CVE-2026-40472 was published on 2026-04-23 and last updated on 2026-06-17.

CVE-2026-40472

CVE-2026-40472 is a critical-severity vulnerability with a CVSS 3.x base score of 9.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Critical (CVSS 3.x base score 9.9)
EPSS exploit prediction: 0% (22nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-25235
Weakness: CWE-79
Published: 2026-04-23
Last modified: 2026-06-17

Description

In hackage-server, user-controlled metadata from .cabal files are rendered into HTML href attributes without proper sanitization, enabling stored Cross-Site Scripting (XSS) attacks.

Frequently asked questions

What is CVE-2026-40472?: In hackage-server, user-controlled metadata from .cabal files are rendered into HTML href attributes without proper sanitization, enabling stored Cross-Site Scripting (XSS) attacks.
How severe is CVE-2026-40472?: CVE-2026-40472 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.
Is CVE-2026-40472 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-40472?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-40472 have an EU (EUVD) identifier?: Yes. CVE-2026-40472 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-25235.
When was CVE-2026-40472 published?: CVE-2026-40472 was published on 2026-04-23 and last updated on 2026-06-17.

References

https://osv.dev/vulnerability/HSEC-2026-0004

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