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Fencer Vulns
medium 6.5

CVE-2020-3134 json

Cisco Email Security Appliance Zip Decompression Engine Denial of Service Vulnerability

published 2020-01-26 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-24405

cvss
6.5
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 65%
public exploits
0
none known

Summary

A vulnerability in the zip decompression engine of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper validation of zip files. An attacker could exploit this vulnerability by sending an email message with a crafted zip-compressed attachment. A successful exploit could trigger a restart of the content-scanning process, causing a temporary DoS condition. This vulnerability affects Cisco AsyncOS Software for Cisco ESA releases earlier than 13.0.

Patch / fix

  • cisco email_security_appliance 13.0

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
23 mo ago

Exploit prediction

1.09% chance of exploitation in the next 30 days, higher than 65% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.0 6.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:N/I:P/A:P

Affected products

  • Cisco Cisco Email Security Appliance (ESA)

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.