CVE-2021-34740

Cisco Aironet Access Points WLAN Control Protocol Packet Buffer Leak Denial of Service Vulnerability

HIGH

7.4

CVSS Score

Published: September 23, 2021 at 02:26 AM UTC

Updated: June 17, 2026 at 03:56 AM UTC

71 products affected across 1 vendorAironet Access Point1100 Integrated Services Router1160 Integrated Services Router

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Severity

HIGH7.4

Exploit prediction

EPSS 0.4%

SSVC

No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Aironet Access Point · Cisco

95%

8.10.0 ≤ v < 8.10.162.017.2 17.3

Affected range stops below 8.10.162.0, so it looks safe — our inference, not a vendor statement

cisco-1100-4g-6g-integrated-services-router (environment) · cisco-1100-4p-integrated-services-router (environment) · cisco-1100-8p-integrated-services-router (environment) · cisco-1100-integrated-services-router (environment) · cisco-1101-4p-integrated-services-router (environment) · cisco-1101-integrated-services-router (environment) · cisco-1109-2p-integrated-services-router (environment) · cisco-1109-4p-integrated-services-router (environment) · cisco-1109-integrated-services-router (environment) · cisco-1111x-8p-integrated-services-router (environment) · cisco-1111x-integrated-services-router (environment) · cisco-111x-integrated-services-router (environment) · cisco-1120-integrated-services-router (environment) · cisco-1160-integrated-services-router (environment) · cisco-6300-series-access-points (environment) · cisco-aironet-1540 (environment) · cisco-aironet-1542d (environment) · cisco-aironet-1542i (environment) · cisco-aironet-1560 (environment) · cisco-aironet-1562d (environment) · cisco-aironet-1562e (environment) · cisco-aironet-1562i (environment) · cisco-aironet-1800 (environment) · cisco-aironet-1800i (environment) · cisco-aironet-1810 (environment) · cisco-aironet-1810w (environment) · cisco-aironet-1815 (environment) · cisco-aironet-1815i (environment) · cisco-aironet-1830 (environment) · cisco-aironet-1830e (environment) · cisco-aironet-1830i (environment) · cisco-aironet-1840 (environment) · cisco-aironet-1850 (environment) · cisco-aironet-1850e (environment) · cisco-aironet-1850i (environment) · cisco-aironet-2800 (environment) · cisco-aironet-2800e (environment) · cisco-aironet-2800i (environment) · cisco-aironet-3800 (environment) · cisco-aironet-3800e (environment) · cisco-aironet-3800i (environment) · cisco-aironet-3800p (environment) · cisco-aironet-4800 (environment) · cisco-catalyst-9100 (environment) · cisco-catalyst-9105 (environment) · cisco-catalyst-9105axi (environment) · cisco-catalyst-9105axw (environment) · cisco-catalyst-9115 (environment) · cisco-catalyst-9115-ap (environment) · cisco-catalyst-9115axe (environment) · cisco-catalyst-9115axi (environment) · cisco-catalyst-9117 (environment) · cisco-catalyst-9117-ap (environment) · cisco-catalyst-9117axi (environment) · cisco-catalyst-9120 (environment) · cisco-catalyst-9120-ap (environment) · cisco-catalyst-9120axe (environment) · cisco-catalyst-9120axi (environment) · cisco-catalyst-9120axp (environment) · cisco-catalyst-9124 (environment) · cisco-catalyst-9124axd (environment) · cisco-catalyst-9124axi (environment) · cisco-catalyst-9130 (environment) · cisco-catalyst-9130-ap (environment) · cisco-catalyst-9130axe (environment) · cisco-catalyst-9130axi (environment) · cisco-catalyst-iw6300 (environment) · cisco-catalyst-iw6300-ac (environment) · cisco-catalyst-iw6300-dc (environment) · cisco-catalyst-iw6300-dcw (environment)

1100-4G/6G Integrated Services Router · Ciscodevice

80%

All versions

1100-4P Integrated Services Router · Ciscodevice

80%

All versions

1100-8P Integrated Services Router · Ciscodevice

80%

All versions

1100 Integrated Services Router · Ciscodevice

80%

All versions