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Vulnerability record · CVE-2021-34740 · published 23 September 2021

CVE-2021-34740: Cisco aironet access point software memory leak vulnerability

Cisco · Aironet Access Point Software

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) condition. This 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.

7.4 CVSS 3.1 High EPSS 0.36% · top 72.4% CWE-401 · Memory leak
7.4CVSS 3.1 base score, v2 6.1
0.36%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

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) condition. This 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.

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Affected products

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

References

LinkTags
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-airo-wpa-pktleak-dos-uSTyGrL Vendor Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-airo-wpa-pktleak-dos-uSTyGrL Vendor Advisory

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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-2021-34740), CISA KEV, FIRST EPSS (scores of 2026-10-06). This page is refreshed as NVD updates the record.