What is CVE-2025-42599?

CVE-2025-42599 is a critical-severity vulnerability in Qualitia Active\! Mail, classified under Stack-based Buffer Overflow. CVSS score: 9.8/10. Published 2025-04-18.

How severe is CVE-2025-42599?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2025-42599 known to be exploited?

Yes. CVE-2025-42599 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-04-28), indicating it is being actively exploited. 6 public proof-of-concept repositories are indexed.

Buffer overflow in Qualitia Active\! Mail

CVE-2025-42599

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.

Vulnerability class: Buffer Overflow

Published 2025-04-18 · last modified 2026-09-24.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.033 (88.3th percentile), scored 2026-10-19.

Low probability of exploitation in the next 30 days, but still tracked. 88th percentile — 88.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.033 · newest: 0.033 · change: 0.000

Affected products

Qualitia Active\! Mail
Qualitia Co., Ltd. Active! Mail 6 — versions BuildInfo: 6.60.05008561 and earlier

Weakness classification (CWE)

CWE-121 — Stack-based Buffer Overflow

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2025-04-28. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2025-05-19.

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.

Public proof-of-concept exploits

References

www.qualitia.com/jp/news/2025/04/18_1030.html (Vendor Advisory)
jvn.jp/en/jp/JVN22348866/ (Third Party Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2025-42599?: CVE-2025-42599 is a critical-severity vulnerability in Qualitia Active\! Mail, classified under Stack-based Buffer Overflow. CVSS score: 9.8/10. Published 2025-04-18.
How severe is CVE-2025-42599?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2025-42599 known to be exploited?: Yes. CVE-2025-42599 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-04-28), indicating it is being actively exploited. 6 public proof-of-concept repositories are indexed.