{"id":"CVE-2021-34740","title":"Cisco Aironet Access Points WLAN Control Protocol Packet Buffer Leak Denial of Service Vulnerability (CVE-2021-34740)","summary":"A vulnerability in the WLAN Control Protocol (WCP) implementation for Cisco Aironet Access Point (AP) software could allow an unauthenticated, adjacent attacker to cause a reload of an affected device, resulting in a denial of service (DoS…","severity":"high","cvss":7.4,"cvssVector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","cvssSource":"vendor","vendor":"Cisco","product":"Cisco Aironet Access Point Software","affected":["aironet_access_point_software","aironet_access_point_software_ios_xe_controller"],"published":"2021-09-22","updated":"2021-09-22","sourceUpdated":"2021-09-22T16:00:00+00:00","source":"CSAF","sourceUrl":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-airo-wpa-pktleak-dos-uSTyGrL","references":[{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-airo-wpa-pktleak-dos-uSTyGrL"},{"url":"https://software.cisco.com"}],"tags":["csaf","vendor-advisory","cisco"],"epss":0.0036,"epssPercentile":0.29851,"ingestedAt":"2026-09-08T15:58:18.543Z","slug":"CVE-2021-34740","body":"## Overview\n\nA vulnerability in the WLAN Control Protocol (WCP) implementation for Cisco Aironet Access Point (AP) software could allow an unauthenticated, adjacent attacker to cause a reload of an affected device, resulting in a denial of service (DoS) condition.\r\n\r\nThis vulnerability is due to incorrect error handling when an affected device receives an unexpected 802.11 frame. An attacker could exploit this vulnerability by sending certain 802.11 frames over the wireless network to an interface on an affected AP. A successful exploit could allow the attacker to cause a packet buffer leak. This could eventually result in buffer allocation failures, which would trigger a reload of the affected device.\r\n\r\nCisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.\n\n## Vendor advisories\n\n- **cisco-sa-airo-wpa-pktleak-dos-uSTyGrL** · Cisco · affected: Cisco Aironet Access Point Software, Cisco Aironet Access Point Software (IOS XE Controller) · updated 2021-09-22 · [advisory](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-airo-wpa-pktleak-dos-uSTyGrL)\n\n**Cisco Aironet Access Points WLAN Control Protocol Packet Buffer Leak Denial of Service Vulnerability**. Released 2021-09-22.\n\nAffected:\n\n- Cisco Aironet Access Point Software\n- Cisco Aironet Access Point Software (IOS XE Controller)\n\n## Remediation\n\nCisco has released software updates that address this vulnerability. https://software.cisco.com","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":40.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}