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Vulnerability record · CVE-2015-6321 · published 6 November 2015

CVE-2015-6321: Cisco web security appliance vulnerability

Cisco · Web Security Appliance

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 9.6.0-042 on Email Security Appliance (ESA) devices; before 9.1.0-032, 9.1.1 before 9.1.1-005, and 9.5.x before 9.5.0-025 on Content Security Management Appliance (SMA) devices; and before 7.7.0-725 and 8.x before 8.0.8-113 on Web Security Appliance (WSA) devices allows remote attackers to cause a denial of service (memory consumption) via a flood of TCP packets, aka Bug IDs CSCus79774, CSCus79777, and CSCzv95795.

7.8 CVSS 2.0 High EPSS 2.8% · top 14.3% CWE-399 · CWE-399
7.8CVSS 2.0 base score
2.8%EPSS exploitation probability, 30 days
NoNot in CISA KEV
3Affected product versions listed by NVD
6References
17 Jun 2026Last modified by NVD

Description

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 9.6.0-042 on Email Security Appliance (ESA) devices; before 9.1.0-032, 9.1.1 before 9.1.1-005, and 9.5.x before 9.5.0-025 on Content Security Management Appliance (SMA) devices; and before 7.7.0-725 and 8.x before 8.0.8-113 on Web Security Appliance (WSA) devices allows remote attackers to cause a denial of service (memory consumption) via a flood of TCP packets, aka Bug IDs CSCus79774, CSCus79777, and CSCzv95795.

AV:N/AC:L/Au:N/C:N/I:N/A:C

Affected products

3 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151104-aos Vendor Advisory
http://www.securitytracker.com/id/1034060
http://www.securitytracker.com/id/1034061
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151104-aos Vendor Advisory
http://www.securitytracker.com/id/1034060
http://www.securitytracker.com/id/1034061

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2015-6321), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.