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Findings

Vulnerability · CVE-2026-32661

Stack-based buffer overflow vulnerability exists in GUARDIANWALL MailSuite and GUARDIANWALL Mail Security Cloud (SaaS version).

Published May 13, 2026 · corrected/updated Jun 17, 2026 · Canon Marketing Japan Inc. GUARDIANWALL MailSuite · evidence confidence very high

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.

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2026-32661 is a critical public vulnerability record for Canon Marketing Japan Inc. GUARDIANWALL MailSuite. CISA lists it as known exploited. Published remediation guidance: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether Canon Marketing Japan Inc. GUARDIANWALL MailSuite is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: Canon Marketing Japan Inc. GUARDIANWALL MailSuite. Published remediation guidance: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 9.3, EPSS 0.7%. CISA lists it as known exploited. Weakness classes: CWE-121. Sources contributing to this record: cve_org, epss, nvd, vulncheck_kev. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Confirmed in CISA KEV since May 13, 2026. Listed in CISA KEV and VulnCheck KEV.

  • Patch and remediation

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. May 13, 2026 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

  2. May 13, 2026 · NIST NVD

    Detected

    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.

  3. Jun 17, 2026 · NIST NVD

    Updated

    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

  • vendor Canon Marketing Japan Inc. GUARDIANWALL MailSuiteversion unspecified

Sources

  • CVE.orgVulnerability recordCVE-2026-32661

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-32661

    30-day exploitation probability 0.7%

    first.org
  • NIST NVDVulnerability recordCVE-2026-32661

    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 ru

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2026-32661

    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 ru

    vulncheck.com

References