How severe is CVE-2026-40874?

CVE-2026-40874 has a CVSS 4.0 base score of 6.0, rated medium severity.

Is CVE-2026-40874 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-40874?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-40874 have an EU (EUVD) identifier?

Yes. CVE-2026-40874 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24256.

When was CVE-2026-40874 published?

CVE-2026-40874 was published on 2026-04-21 and last updated on 2026-06-17.

CVE-2026-40874

CVE-2026-40874 is a medium-severity vulnerability with a CVSS 4.0 base score of 6.0. 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: Medium (CVSS 4.0 base score 6.0)
EPSS exploit prediction: 0% (7th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-24256
Weakness: CWE-284
Published: 2026-04-21
Last modified: 2026-06-17

Description

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, no administrator verification takes place when deleting Forwarding Hosts with `/api/v1/delete/fwdhost`. Any authenticated user can call this API. Checks are only applied for edit/add actions, but deletion can still significantly disrupt the mail service. Version 2026-03b fixes the vulnerability.

Frequently asked questions

What is CVE-2026-40874?: mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, no administrator verification takes place when deleting Forwarding Hosts with `/api/v1/delete/fwdhost`. Any authenticated user can call this API. Checks are only applied for edit/add actions, but deletion can still significantly disrupt the mail service. Version 2026-03b fixes the vulnerability.
How severe is CVE-2026-40874?: CVE-2026-40874 has a CVSS 4.0 base score of 6.0, rated medium severity.
Is CVE-2026-40874 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-40874?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-40874 have an EU (EUVD) identifier?: Yes. CVE-2026-40874 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24256.
When was CVE-2026-40874 published?: CVE-2026-40874 was published on 2026-04-21 and last updated on 2026-06-17.

References

https://github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-jjxh-rm7p-hjc3

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