5.3Medium

Cisco Adaptive Security Appliance

CVE-2021-34787

A vulnerability in the identity-based firewall (IDFW) rule processing feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass security protections. This vulnerability is due to improper handling of network requests by affected devices configured to use object group search. An attacker could exploit this vulnerability by sending a specially crafted network request to an affected device. A successful exploit could allow the attacker to bypass access control list (ACL) rules on the device, bypass security protections, and send network traffic to unauthorized hosts.

What this means for your business

  • It affects Cisco Adaptive Security Appliance. 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 Adaptive Security Appliance, 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.

Scoring

CVSS
5.3 (v3.1)
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness
CWE-183
Assigned by
psirt@cisco.com

Dates

Published
2021-10-27
Last modified
2026-08-11
Sources
NVD

Affected products

  • Cisco Adaptive Security Appliance- 9.8.4.40
  • Cisco Secure Firewall Threat Defense- 6.4.0.13, 6.5.0 - 6.6.5, 6.7.0 - 6.7.0.3, 7.0.0 - 7.0.1
  • Cisco Adaptive Security Appliance Software9.9.0 - 9.12.4.25, 9.13.0 - 9.14.3.1, 9.15.0 - 9.15.1.17, 9.16.0 - 9.16.1.28
  • Cisco Asa 5512-X Firmware009.009, 009.012
  • Cisco Asa 5512-Xall versions
  • Cisco Asa 5505 Firmware009.009, 009.012
  • Cisco Asa 5505all versions
  • Cisco Asa 5515-X Firmware009.009, 009.012
  • Cisco Asa 5515-Xall versions
  • Cisco Asa 5525-X Firmware009.009, 009.012
  • Cisco Asa 5525-Xall versions
  • Cisco Asa 5545-X Firmware009.009, 009.012

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

References