TI-2018-00406 Aliases CVE-2018-0447 GHSA-6x9p-wvp8-hwgq

Cisco Email Security Appliance URL Filtering Bypass Vulnerability

LOW 34CWE-284Published 2018-10-05 · Updated 2024-11-26

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Security bypass
Confidentiality · integrity · availability: None · Low · None
Fix status: No fix listed

Attack profile from CVSS 3.0 · NVD. Fix status from CNA. Impact type from CWE-284.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.02276 83rd percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Cisco	Cisco Email Security Appliance (ESA)	all versions	—	No fix listed	CNA

Cisco Email Security Appliance (ESA) VendorCisco Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:cisco:email_security_appliance:-:::::::*	not specified by NVD	Vulnerable	Cisco

cpe:2.3:a:cisco:email_security_appliance:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Cisco

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2018-0447
2026-10-03 Alias added: GHSA-6x9p-wvp8-hwgq

References

Advisory 1

20180905 Cisco Email Security Appliance URL Filtering Bypass Vulnerability

TI-2022-05357 Cisco Email Security Appliance and Cisco Secure Email and Web Manager External Authentication Bypass Vulnerability CVSS 3.1CRITICAL 9.8
TI-2019-01567 Cisco Email Security Appliance Denial of Service Vulnerability CVSS 3.1HIGH 8.6
TI-2018-00378 Improper input validation in Cisco Email Security Appliance CVSS 3.0HIGH 7.5
TI-2020-02695 Cisco Email Security Appliance Content Filter Bypass Vulnerability CVSS 3.1HIGH 7.5
TI-2019-01541 Cisco Email Security Appliance Content Filter Bypass Vulnerability CVSS 3.0HIGH 7.5
TI-2019-01553 Cisco Email Security Appliance Content Filter Bypass Vulnerability CVSS 3.0HIGH 7.4

See all 49 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences