Vulnerability · Published May 13, 2026 · Assigned by jpcert

CVE-2026-32661

Critical 9.8

In plain English

A critical-severity stack buffer overflow in GUARDIANWALL Mail Security Cloud (SaaS version) from Canon Marketing Japan Inc.. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities).

Severity (CVSS 3.0)9.8Critical

Exploit odds (30 days)0.5%top 59.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Stack-based buffer overflow vulnerability exists in GUARDIANWALL MailSuite and GUARDIANWALL Mail Security Cloud (SaaS version). If a remote attacker sends a specially crafted request to the product's web service, arbitrary code may be executed when the product is configured to run pop3wallpasswd with grdnwww user privilege.

Affected products (as reported)

Vendor	Product	Versions
Canon Marketing Japan Inc.	GUARDIANWALL MailSuite (On-premises version)	Ver 1.4.00 to Ver 2.4.26
Canon Marketing Japan Inc.	GUARDIANWALL Mail Security Cloud (SaaS version)	versions before the maintenance on April 302026

Weakness: CWE-121 · Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

In plain English

Official description

Affected products (as reported)

References