Cisco Secure Email Gateway Security Hardening Release (CVE-2026-20353) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-20353

Cisco Secure Email Gateway Security Hardening Release

Answer in brief

CVE-2026-20353 records a Unknown severity vulnerability in Cisco Secure Email Gateway Security Hardening Release. The current sources do not mark it as known exploited. The current feed maps Cisco/Cisco Secure Email (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 14, 2026Updated Sep 14, 2026Source checked Sep 14, 2026First seen by HOL Sep 14, 2026Material review Sep 14, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Cisco/Cisco Secure Email (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Cisco/Cisco Secure Emailgeneric	14.0.0-698 \|\| 13.5.1-277 \|\| 13.0.0-392 \|\| 14.2.0-620 \|\| 13.0.5-007 \|\| 13.5.4-038 \|\| 14.2.1-020 \|\| 14.3.0-032 \|\| 15.0.0-104 \|\| 15.0.1-030 \|\| 15.5.0-048 \|\| 15.5.1-055 \|\| 15.5.2-018 \|\| 16.0.0-050 \|\| 15.0.3-002 \|\| 16.0.0-054 \|\| 15.5.3-022 \|\| 16.0.1-017 \|\| 15.5.4-012 \|\| 16.0.4-016 \|\| 15.0.5-016 \|\| 16.0.2-112 \|\| 16.0.3-044	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Cisco/Cisco Secure Email.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Sep 14, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 14, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 14, 2026

Sources and claim methodology

Source referencesec.cloudapps.cisco.com

Upstream source description

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Secure Email Gateway and Cisco Secure Email and Web Manager engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20353 are related to issues with improper control of a resource through its lifetime that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-664.

Quoted source text, attributed separately from HOL analysis.