CVE-2018-0447

mediumpriority · track · 22EPSS 0.023 · 83 %ileEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

2.28% (83rd) EPSS

CVSS 5 · medium

Is it mine?

4 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · cisco_csaf

EPSS · scored 2026-10-27

A vulnerability in the anti-spam protection mechanisms of Cisco AsyncOS Software for the Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass certain content filters on an affected device. The vulnerability is due to incomplete input and validation checking mechanisms for certain Sender Policy Framework (SPF) messages that are sent to an affected device. An attacker could exploit this vulnerability by sending a customized SPF packet to an affected device. If successful, an exploit could allow the attacker to bypass the URL filters that are configured for the affected device, which could allow malicious URLs to pass through the device.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

FixedCisco Email Security Appliance (ESA)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com

cvss

Technical severity, 0–10. One row per scoring source.

5.3

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.05mediumAV:N/AC:L/Au:N/C:N/I:P/A:Nprimary · NVD / NIST USexploitability 10 · impact 2.9

v3.05.3mediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 1.4

v3.04.9mediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:Usecondary · CVSS-BT (t0sche)

v3.05.3mediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:Nsecondary · Cisco PSIRT US

v3.15.3mediumAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:Nsecondary · FSTEC (BDU) RU

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-20USprimaryCWE-284USCWE-284US

affected products (4)

Products and version ranges known to be affected.

Cisco Cisco Email Security Appliance (ESA)all versionscisco_csafUS
Cisco Cisco Email Security Appliance (ESA)≤ n/aenisa_euvdEU
Cisco Systems Inc. Cisco Email Security Appliancesall versionsfstec_bduRU
cisco email security applianceall versionsnvdUScpe:2.3:a:cisco:email_security_appliance:*:*:*:*:*:*:*:*

advisories (1)

Vendor and ecosystem advisories describing this.

cisco-sa-20180905-esa-url-bypassCisco Email Security Appliance URL Filtering Bypass Vulnerability2018-09-05csaf · cisco_csafUS
A vulnerability in the anti-spam protection mechanisms of Cisco AsyncOS Software for the Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass certain content filters on an affected device. The vulnerability is due to incomplete input and validation checking mechanisms for certain Sender Policy Framework (SPF) messages that are sent to an affected device. An attacker could exploit this vulnerability by sending a customized SPF packet to an affected device. If successful, an exploit could allow the attacker to bypass the URL filters that are configured for the affected device, which could allow malicious URLs to pass through the device. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180905-esa-url-bypass ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180905-esa-url-bypass"]

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu cisco_csaf nvd NVD CVE.org MITRE

published 2018-10-05modified 2026-06-17

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references (9)

External citations — patches, advisories, analysis.

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