CVE-2020-3134Network attack vector

Service interruption via malformed ZIP attachment

Published Jan 26, 2020 · Updated Nov 15, 2024

Improper input validation in Cisco AsyncOS before 13.0 allows remote attackers to interrupt email scanning with a crafted ZIP attachment. The ZIP decompression engine fails to validate a malformed archive before processing it, causing the content-scanning process to restart. Unauthenticated delivery of the attachment is sufficient, and exploitation temporarily interrupts content scanning rather than the entire appliance.

CVSS severity6.5
Medium
EPSS probability1.09%
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 AsyncOS before 13.0 allows remote attackers to interrupt email scanning with a crafted ZIP attachment. The ZIP decompression engine fails to validate a malformed archive before processing it, causing the content-scanning process to restart. Unauthenticated delivery of the attachment is sufficient, and exploitation temporarily interrupts content scanning rather than the entire appliance.

The record

CVE
CVE-2020-3134
Published
Jan 26, 2020
Updated
Nov 15, 2024
Vendor
ClamAV
Product
Cisco Secure Email Gateway
Classifications
CWE-20, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 26, 2020CVE publishedPublication date reported by the CVE source.
  2. Nov 15, 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=earlier than 13.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Secure Email Gatewayversion=earlier than 13.0

Published CVSS scores

6.4NIST NVDAV:N/AC:L/Au:N/C:N/I:P/A:P
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
6.5Cisco Systems, Inc.CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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-20Improper Input Validation
T1499Endpoint Denial of Service

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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