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TI-2020-03092 Aliases CVE-2020-3548GHSA-r24r-r242-xm9f

Cisco Email Security Appliance Denial Of Service Vulnerability

Priority MEDIUM 40CWE-407Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-407.

Summary

A vulnerability in the Transport Layer Security (TLS) protocol implementation of Cisco AsyncOS software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to cause high CPU usage on an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to inefficient processing of incoming TLS traffic. An attacker could exploit this vulnerability by sending a series of crafted TLS packets to an affected device. A successful exploit could allow the attacker to trigger a prolonged state of high CPU utilization. The affected device would still be operative, but response time and overall performance may be degraded.There are no workarounds that address this vulnerability.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00843 58th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
CiscoCisco Secure EmailN/A—No fix listedCNA
  • Cisco Secure Email VendorCisco Affected N/A Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:cisco:email_security_appliance:*:*:*:*:*:*:*:*up to 13.5.1-277VulnerableCisco
  • cpe:2.3:a:cisco:email_security_appliance:*:*:*:*:*:*:*:* Versions up to 13.5.1-277 Vulnerable ·Cisco

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2020-3548
  2. 2026-10-03 Alias added: GHSA-r24r-r242-xm9f

References

Advisory 1

  • TI-2022-05357 Cisco Email Security Appliance and Cisco Secure Email and Web Manager External Authentication Bypass Vulnerability CVSS 3.1CRITICAL 9.8
  • TI-2019-01567 Cisco Email Security Appliance Denial of Service Vulnerability CVSS 3.1HIGH 8.6
  • TI-2018-00378 Improper input validation in Cisco Email Security Appliance CVSS 3.0HIGH 7.5
  • TI-2020-02695 Cisco Email Security Appliance Content Filter Bypass Vulnerability CVSS 3.1HIGH 7.5
  • TI-2019-01541 Cisco Email Security Appliance Content Filter Bypass Vulnerability CVSS 3.0HIGH 7.5
  • TI-2019-01553 Cisco Email Security Appliance Content Filter Bypass Vulnerability CVSS 3.0HIGH 7.4
See all 49 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences