CVE-2026-20052Network attack vector

Detection-engine restart via SSL memory mismanagement

Published Mar 4, 2026 · Updated Mar 4, 2026

Denial of service in Cisco Secure Firewall Threat Defense allows remote attackers to restart its Snort 3 Detection Engine. A memory-management logic error during SSL packet inspection mishandles crafted SSL packets sent through an established connection. Exploitation requires Snort 3 and a nondefault SSL policy to be enabled; successful attacks interrupt inspection by unexpectedly restarting the engine.

CVSS severity5.8
Medium
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Cisco Secure Firewall Threat Defense allows remote attackers to restart its Snort 3 Detection Engine. A memory-management logic error during SSL packet inspection mishandles crafted SSL packets sent through an established connection. Exploitation requires Snort 3 and a nondefault SSL policy to be enabled; successful attacks interrupt inspection by unexpectedly restarting the engine.

The record

CVE
CVE-2026-20052
Published
Mar 4, 2026
Updated
Mar 4, 2026
Vendor
ClamAV
Product
Cisco Secure Firewall Threat Defense
Classifications
CWE-788, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=7.4.0
  2. Affected versionversion=7.4.1
  3. Affected versionversion=7.4.1.1
  4. Affected versionversion=7.4.2
  5. Affected versionversion=7.4.2.1
  6. Affected versionversion=7.6.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Secure Firewall Threat Defenseversion=7.4.0; version=7.4.1; version=7.4.1.1; version=7.4.2; version=7.4.2.1; version=7.6.0

Published CVSS scores

5.8Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L/E:X/RL:X/RC:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-788Access of Memory Location After End of Buffer
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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