CVE-2009-4921: Cisco Adaptive Security Appliances (ASA) 5580 series devices with software before 8.1(2) allow remote attac...

Security readout for executives and security teams

This vulnerability affects Cisco ASA 5580 firewalls running ASA software before 8.1(2). A remote attacker could send malformed TCP traffic that causes a denial of service traceback, potentially disrupting firewall availability. The provided sources do not show data theft, code execution, or confirmed active exploitation. Exposure is likely limited to organizations still operating Cisco ASA 5580 series devices on ASA software earlier than 8.1(2). Inventory quality matters because the CVE record’s structured affected-product data is incomplete. Treat this as a targeted availability risk for legacy perimeter infrastructure. It is not documented as actively exploited, but an affected firewall outage could disrupt business connectivity and security enforcement. Mitigation focus: Identify any Cisco ASA 5580 devices in production or backup paths.; Check running ASA software versions against the 8.1(2) threshold.; Upgrade affected devices to 8.1(2) or a later vendor-supported release..

Prepared

Jun 28, 2026, 02:01 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.