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Fencer Vulns
medium 5.8

CVE-2017-12353 json

A vulnerability in the Multipurpose Internet Mail Extensions (MIME) scanner of Cisco AsyncOS Software for Cisco Email Security Appliances (…

published 2017-11-30 8 y ago modified 2026-06-17 4 mo ago also EUVD-2017-3926

cvss
5.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

A vulnerability in the Multipurpose Internet Mail Extensions (MIME) scanner of Cisco AsyncOS Software for Cisco Email Security Appliances (ESA) could allow an unauthenticated, remote attacker to bypass configured user filters on the device. The vulnerability is due to improper error handling of a malformed MIME header in an email attachment. An attacker could exploit this vulnerability by sending an email with a crafted MIME attachment. For example, a successful exploit could allow the attacker to bypass configured user filters to drop the email. The malformed MIME headers may not be RFC compliant. However, some mail clients could still allow users to access the attachment, which may not have been properly filtered by the device. Cisco Bug IDs: CSCvf44666.

Exploit prediction

1.64% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 5.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N

Affected products

  • n/a Cisco Email Security Appliance

Classification

Weakness

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.