CVE-2019-1886

Cisco Web Security Appliance HTTPS Certificate Denial of Service Vulnerability

HIGH

8.6

CVSS Score

Published: July 4, 2019 at 07:50 PM UTC

Updated: June 17, 2026 at 02:29 AM UTC

2 products affected across 1 vendorWeb Security ApplianceAsyncos

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Severity

HIGH8.6

Exploit prediction

EPSS 1%

SSVC

No known exploit

Description

A vulnerability in the HTTPS decryption feature of Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to insufficient validation of Secure Sockets Layer (SSL) server certificates. An attacker could exploit this vulnerability by installing a malformed certificate in a web server and sending a request to it through the Cisco WSA. A successful exploit could allow the attacker to cause an unexpected restart of the proxy process on an affected device.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Asyncos · Cisco

95%

10.5 ≤ v < 10.5.5-00511.5 ≤ v < 11.5.2-020

Affected range stops below 10.5.5-005, so it looks safe — our inference, not a vendor statement

Affected range stops below 11.5.2-020, so it looks safe — our inference, not a vendor statement

Web Security Appliance · Cisco

95%

v < 10.5.5-00510.5.2-072 10.5.3-025 11.7.0-fcs-334

Affected range stops below 10.5.5-005, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190703-wsa-dos

References (2)

VDB Entryx_refsource_BIDThird Party Advisory

Source: [email protected]

http://www.securityfocus.com/bid/109049

Vendor Advisoryx_refsource_CISCO

Source: [email protected]

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190703-wsa-dos

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.6HIGH[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: CHANGED
Confidentiality: NONE
Integrity: NONE
Availability: HIGH

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-20CWE-295

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