CVE-2026-20353

CRITICALCVSS 9.8/10EPSS 0.37%

Last modified

CVE-2026-20353 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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.. EPSS estimates a 0.37% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
0.37%

30.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
CiscoCisco Secure Email14.0.0-698; 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

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-20353?
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.
How severe is CVE-2026-20353?
CVE-2026-20353 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.37% probability of exploitation in the next 30 days.
How do I fix CVE-2026-20353?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST