---
title: "CVE-2025-42599: Qualitia Active! Mail Stack-Based Buffer Overflow Vulnerability"
url: https://erroneo.us/security/cve/CVE-2025-42599/
description: "CVE-2025-42599 (Qualitia Active! Mail): Exploited in the wild (CISA KEV). Active! mail 6 BuildInfo: 6.60.05008561 and earlier contains a stack-based buffer…"
type: vulnerability-record
section: "Security Digest"
date_published: 2025-04-18
date_modified: 2026-02-26
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2025-42599"
kev: true
cvss: 9.8
epss: 0.03355
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2025-42599: Qualitia Active! Mail Stack-Based Buffer Overflow Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Qualitia Active! Mail. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2025-04-28, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2025-05-19 ; treat that as the outer limit, not the target.
- EPSS 3.4% , percentile 89: FIRST’s model estimates a 3.4% chance of exploitation activity in the next 30 days, higher than 89% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.

## What it is

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.

## Affected products (CVE record)

- QUALITIA CO., LTD. Active! mail 6: BuildInfo: 6.60.05008561 and earlier

## Severity

- jpcert CVSS 3.0: 9.8 `CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: added 2025-04-28; federal due date 2025-05-19. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 3.36% probability of exploitation activity in the next 30 days; percentile 89.

## Sources

- [Listed in CISA KEV notes (qualitia.com)](https://www.qualitia.com/jp/news/2025/04/18_1030.html)
- [CVE.org record CVE-2025-42599](https://www.cve.org/CVERecord?id=CVE-2025-42599)
- [NVD entry CVE-2025-42599](https://nvd.nist.gov/vuln/detail/CVE-2025-42599)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-42599)
- [jvn.jp](https://jvn.jp/en/jp/JVN22348866/)

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Source page: https://erroneo.us/security/cve/CVE-2025-42599/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt