Cisco Web Security Appliance Proxy Service Denial of Service Vulnerability

Description

A vulnerability in the proxy service of Cisco AsyncOS for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to exhaust system memory and cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper memory management in the proxy service of an affected device. An attacker could exploit this vulnerability by establishing a large number of HTTPS connections to the affected device. A successful exploit could allow the attacker to cause the system to stop processing new connections, which could result in a DoS condition. Note: Manual intervention may be required to recover from this situation.

Scores

EPSS (exploitation in 30 days)

1.4% · top 27% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: yes · Technical impact: total

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.6.

Weakness

• CWE-401 (opens in a new tab)All about CWE-401 and its CVEs

Affected products

• Cisco · Cisco Web Security Appliance (WSA)

  • affected n/a

What to do

Exploitation: The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.

References (1)

• 20211006 Cisco Web Security Appliance Proxy Service Denial of Service Vulnerability (opens in a new tab)vendor-advisoryx_refsource_CISCOx_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2021-34698](https://trackcve.app/badge/CVE-2021-34698.svg)](https://trackcve.app/cve/CVE-2021-34698)

Record last updated 7 Nov 2024, 21:47 UTC.