How severe is CVE-2025-40631?

CVE-2025-40631 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2025-40631 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-40631?

CVE-2025-40631 affects Icewarp Mail Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-40631?

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

Does CVE-2025-40631 have an EU (EUVD) identifier?

Yes. CVE-2025-40631 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-15437.

When was CVE-2025-40631 published?

CVE-2025-40631 was published on 2025-05-16 and last updated on 2026-06-17.

CVE-2025-40631

CVE-2025-40631 is a medium-severity vulnerability in Icewarp Mail Server with a CVSS 3.x base score of 6.1. 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-644.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v4: 2.0
EPSS exploit prediction: 0% (8th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-15437
Weakness: CWE-644
Affected product: Icewarp Mail Server
Published: 2025-05-16
Last modified: 2026-06-17

Description

HTTP host header injection vulnerability in Icewarp Mail Server affecting version 11.4.0. By modifying the Host header and adding a payload, arbitrary JavaScript code can be executed on page load. The user must interact with a malicious link to be redirected.

Frequently asked questions

What is CVE-2025-40631?: HTTP host header injection vulnerability in Icewarp Mail Server affecting version 11.4.0. By modifying the Host header and adding a payload, arbitrary JavaScript code can be executed on page load. The user must interact with a malicious link to be redirected.
How severe is CVE-2025-40631?: CVE-2025-40631 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2025-40631 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-40631?: CVE-2025-40631 affects Icewarp Mail Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-40631?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-40631 have an EU (EUVD) identifier?: Yes. CVE-2025-40631 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-15437.
When was CVE-2025-40631 published?: CVE-2025-40631 was published on 2025-05-16 and last updated on 2026-06-17.

References

https://www.incibe.es/en/incibe-cert/notices/aviso/multiple-vulnerabilities-icewarp-mail-server

Affected products (1)

cpe:2.3:a:icewarp:mail_server:11.4.0:*:*:*:*:*:*:*

More vulnerabilities in Icewarp Mail Server

CVE-2023-39699 — Critical (CVSS 9.8): IceWarp Mail Server v10.4.5 was discovered to contain a local file inclusion (LFI) vulnerability via the component…
CVE-2020-14066 — High (CVSS 8.8): IceWarp Email Server 12.3.0.1 allows remote attackers to upload JavaScript files that are dangerous for clients to…
CVE-2019-12593 — High (CVSS 7.5): IceWarp Mail Server through 10.4.4 is prone to a local file inclusion vulnerability via…
CVE-2015-1503 — High (CVSS 7.5): Multiple directory traversal vulnerabilities in IceWarp Mail Server before 11.2 allow remote attackers to read…
CVE-2020-14065 — Medium (CVSS 6.5): IceWarp Email Server 12.3.0.1 allows remote attackers to upload files and consume disk space.
CVE-2020-14064 — Medium (CVSS 6.5): IceWarp Email Server 12.3.0.1 has Incorrect Access Control for user accounts.

All CVEs affecting Icewarp Mail Server →

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