CVE-2023-20270Network attack vector

Policy bypass and Snort reload via malformed SMB

Published Nov 1, 2023 · Updated Aug 2, 2024

Improper input validation in Cisco Firepower Threat Defense 7.1.0 through 7.3.1.1 allows remote attackers to reload Snort via SMB traffic. The SMB preprocessor fails to check errors correctly while Snort 3 processes a crafted SMB packet stream, causing the detection process to restart. Exposure requires an SMB policy that invokes Snort 3; the reload interrupts inspection and can bypass configured policy according to fail-open and connection-preservation settings.

CVSS severity5.8
Medium
EPSS probability0.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Cisco Firepower Threat Defense 7.1.0 through 7.3.1.1 allows remote attackers to reload Snort via SMB traffic. The SMB preprocessor fails to check errors correctly while Snort 3 processes a crafted SMB packet stream, causing the detection process to restart. Exposure requires an SMB policy that invokes Snort 3; the reload interrupts inspection and can bypass configured policy according to fail-open and connection-preservation settings.

The record

CVE
CVE-2023-20270
Published
Nov 1, 2023
Updated
Aug 2, 2024
Vendor
ClamAV
Product
Cisco Firepower Threat Defense
Classifications
CWE-20, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 1, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record 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=7.1.0
  2. Affected versionversion=7.1.0.1
  3. Affected versionversion=7.1.0.2
  4. Affected versionversion=7.1.0.3
  5. Affected versionversion=7.2.0
  6. Affected versionversion=7.2.0.1
  7. Affected versionversion=7.2.1
  8. Affected versionversion=7.2.2
  9. Affected versionversion=7.2.3
  10. Affected versionversion=7.3.0
  11. Affected versionversion=7.3.1
  12. Affected versionversion=7.3.1.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Firepower Threat Defenseversion=7.1.0; version=7.1.0.1; version=7.1.0.2; version=7.1.0.3; version=7.2.0; version=7.2.0.1; version=7.2.1; version=7.2.2; version=7.2.3; version=7.3.0; version=7.3.1; version=7.3.1.1

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
5.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

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-20Improper Input Validation
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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