How severe is CVE-2026-40866?

CVE-2026-40866 has a CVSS 4.0 base score of 8.6, rated high severity.

Is CVE-2026-40866 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-40866?

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

Does CVE-2026-40866 have an EU (EUVD) identifier?

Yes. CVE-2026-40866 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24234.

When was CVE-2026-40866 published?

CVE-2026-40866 was published on 2026-04-21 and last updated on 2026-06-17.

CVE-2026-40866

CVE-2026-40866 is a high-severity vulnerability with a CVSS 4.0 base score of 8.6. 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-284.

Key facts

Severity: High (CVSS 4.0 base score 8.6)
EPSS exploit prediction: 0% (11th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-24234
Weakness: CWE-284
Published: 2026-04-21
Last modified: 2026-06-17

Description

Horilla is a free and open source Human Resource Management System (HRMS). In 1.5.0, an insecure direct object reference in the employee document upload endpoint allows any authenticated user to overwrite or replace or corrupt another employee’s document by changing the document ID in the upload request. This enables unauthorized modification of HR records.

Frequently asked questions

What is CVE-2026-40866?: Horilla is a free and open source Human Resource Management System (HRMS). In 1.5.0, an insecure direct object reference in the employee document upload endpoint allows any authenticated user to overwrite or replace or corrupt another employee’s document by changing the document ID in the upload request. This enables unauthorized modification of HR records.
How severe is CVE-2026-40866?: CVE-2026-40866 has a CVSS 4.0 base score of 8.6, rated high severity.
Is CVE-2026-40866 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-40866?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-40866 have an EU (EUVD) identifier?: Yes. CVE-2026-40866 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24234.
When was CVE-2026-40866 published?: CVE-2026-40866 was published on 2026-04-21 and last updated on 2026-06-17.

References

https://github.com/horilla/horilla-hr/security/advisories/GHSA-q2qh-v828-r4p7

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