Is CVE-2026-40873 in the CISA KEV catalog?

No. CVE-2026-40873 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the EPSS score for CVE-2026-40873?

CVE-2026-40873 has an EPSS score of 0.33% (24th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix or mitigate CVE-2026-40873?

No published fix for CVE-2026-40873 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

CVE & CISA-KEV Catalog

CVE-2026-40873

UNSCORED

NVD

Description

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the Quarantine details modal injects attachment filenames into HTML without escaping, allowing arbitrary HTML/JS execution. An attacker can deliver an email with a crafted attachment name so that when an admin views the quarantine item, JavaScript executes in their browser, taking over their account. Version 2026-03b fixes the vulnerability.

CWE-79Cross-Site Scripting (XSS)CWE-80

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

CVSS v3.1 Vector

No CVSS vector data available.

Exploit Intelligence

0.33%probability of exploitation in 30 days

24thpercentile

Low risk: more likely to be exploited than 24% of all known CVEs.

References

Other references1

github.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-22.