CyberBrief
Subscribe
5.8Medium

Cisco Secure Firewall Threat Defense

CVE-2020-3299

Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured File Policy for HTTP. The vulnerability is due to incorrect detection of modified HTTP packets used in chunked responses. An attacker could exploit this vulnerability by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass a configured File Policy for HTTP packets and deliver a malicious payload.

What this means for your business

  • It affects Cisco Secure Firewall Threat Defense. It matters if your company, or a supplier that handles your data, runs it.
  • An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.

What to do

  1. 1Check whether your company or your suppliers run Cisco Secure Firewall Threat Defense, and which version. The affected versions are listed further down this page.
  2. 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

Check if you’re exposedBook a call

Scoring

CVSS
5.8 (v3.1)
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Weakness
CWE-693
Assigned by
psirt@cisco.com

Dates

Published
2020-10-21
Last modified
2026-08-11
Sources
NVD

Affected products

  • Cisco Secure Firewall Threat Defense6.0.0 - 6.3.0.1
  • Cisco Cloud Services Router 1000vall versions
  • Cisco Isrvall versions
  • Cisco 1100-4pall versions
  • Cisco 1100-8pall versions
  • Cisco 1101-4pall versions
  • Cisco 1109-2pall versions
  • Cisco 1109-4pall versions
  • Cisco 1111x-8pall versions
  • Cisco 4221 Integrated Services Routerall versions
  • Cisco 4331 Integrated Services Routerall versions
  • Cisco 4431 Integrated Services Routerall versions

As listed in the NVD configuration data. Not a statement about your estate.

References