CVE-2015-6321: Cisco AsyncOS before 8.5.7-042, 9.x before 9.1.0-032, 9.1.x before 9.1.1-023, and 9.5.x and 9.6.x before 9....

Security readout for executives and security teams

Some Cisco email, web, and content security appliances can be forced into excessive memory use by remote TCP packet flooding. The main business risk is appliance instability or outage affecting email security, web filtering, or management visibility. Exposure is most likely where affected Cisco ESA, SMA, or WSA appliances run vulnerable AsyncOS versions and accept network traffic from untrusted or broad network sources. Treat this as a targeted availability risk for legacy Cisco security appliances. Prioritize remediation where these devices protect critical mail, web, or management paths, especially if they are internet-facing or exposed to large untrusted networks. Mitigation focus: Upgrade ESA AsyncOS to 8.5.7-042, 9.1.0-032, 9.1.1-023, or 9.6.0-042 or later as applicable.; Upgrade SMA AsyncOS to 9.1.0-032, 9.1.1-005, or 9.5.0-025 or later as applicable.; Upgrade WSA AsyncOS to 7.7.0-725 or 8.0.8-113 or later as applicable..

Prepared

Jun 13, 2026, 21:45 UTC (UTC+00:00)

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