What is the CVSS score of CVE-2025-42599?

CVE-2025-42599 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 2.8%.

Which versions of Active Mail are affected by CVE-2025-42599?

CVE-2025-42599 presents critical security risk, a stack-based buffer overflow vulnerability rated CVSS 9.8.

Is CVE-2025-42599 being actively exploited?

Yes, CVE-2025-42599 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, confirming active in-the-wild exploitation. Immediate patching is required.

How to fix or mitigate CVE-2025-42599?

Within 24 hours: Identify all affected systems and apply vendor patches immediately. If patching is delayed, consider network segmentation to limit exposure.

Active Mail CVE-2025-42599

CRITICAL

Stack-based Buffer Overflow (CWE-121)

2025-04-18 vultures@jpcert.or.jp

Buffer Overflow RCE Stack Overflow Active Mail

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 18:37 vuln.today

Added to CISA KEV

Oct 24, 2025 - 17:00 cisa

CISA KEV

CVE Published

Apr 18, 2025 - 04:15 nvd

CRITICAL 9.8

DescriptionCVE.org

Active! mail 6 BuildInfo: 6.60.05008561 and earlier contains a stack-based buffer overflow vulnerability. Receiving a specially crafted request created and sent by a remote unauthenticated attacker may lead to arbitrary code execution and/or a denial-of-service (DoS) condition.

AnalysisAI

Active! mail 6 contains a stack-based buffer overflow allowing unauthenticated remote code execution and denial of service through crafted requests, exploited in attacks against Japanese organizations in April 2025.

Technical ContextAI

The CWE-121 stack overflow in Active! mail's request processing allows crafted requests to overflow a stack buffer, enabling arbitrary code execution on the mail server.