CVE-2021-34787: Cisco Adaptive Security Appliance

Medium severity, CVSS 5.3. EPSS: 1% chance of exploitation in the next 30 days.

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.

Affected products

• Cisco Adaptive Security Appliance: before 9.8.4.40 (fixed in 9.8.4.40)
• Cisco Adaptive Security Appliance Software: from 9.9.0, before 9.12.4.25 (fixed in 9.12.4.25); from 9.13.0, before 9.14.3.1 (fixed in 9.14.3.1); from 9.15.0, before 9.15.1.17 (fixed in 9.15.1.17); from 9.16.0, before 9.16.1.28 (fixed in 9.16.1.28)
• Cisco ASA 5505 Firmware: version 009.009 only; version 009.012 only
• Cisco ASA 5512-X Firmware: version 009.009 only; version 009.012 only
• Cisco ASA 5515-X Firmware: version 009.009 only; version 009.012 only
• Cisco ASA 5525-X Firmware: version 009.009 only; version 009.012 only
• Cisco ASA 5545-X Firmware: version 009.009 only; version 009.012 only
• Cisco ASA 5555-X Firmware: version 009.009 only; version 009.012 only
• Cisco ASA 5580 Firmware: version 009.009 only; version 009.012 only
• Cisco ASA 5585-X Firmware: version 009.009 only; version 009.012 only
• Cisco Secure Firewall Threat Defense: before 6.4.0.13 (fixed in 6.4.0.13); from 6.5.0, before 6.6.5 (fixed in 6.6.5); from 6.7.0, before 6.7.0.3 (fixed in 6.7.0.3); from 7.0.0, before 7.0.1 (fixed in 7.0.1)

Published 2021-10-27. Last modified 2026-08-11.