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AUSCERT External Security Bulletin Redistribution
Cisco Embedded Wireless Controller Software for Catalyst
Access Points Denial of Service Vulnerability
23 September 2021
AusCERT Security Bulletin Summary
Product: Embedded Wireless Controller Software
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Denial of Service -- Remote/Unauthenticated
CVE Names: CVE-2021-1615
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Cisco Embedded Wireless Controller Software for Catalyst Access Points Denial
of Service Vulnerability
Advisory ID: cisco-sa-iosxe-ewc-dos-g6JruHRT
First Published: 2021 September 22 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds available
Cisco Bug IDs: CSCvy04449
CVE Names: CVE-2021-1615
o A vulnerability in the packet processing functionality of Cisco Embedded
Wireless Controller (EWC) Software for Catalyst Access Points (APs) could
allow an unauthenticated, remote attacker to cause a denial of service
(DoS) condition on an affected AP.
This vulnerability is due to insufficient buffer allocation. An attacker
could exploit this vulnerability by sending crafted traffic to an affected
device. A successful exploit could allow the attacker to exhaust available
resources and cause a DoS condition on an affected AP, as well as a DoS
condition for client traffic traversing the AP.
Cisco has released software updates that address this vulnerability. There
are no workarounds that address this vulnerability.
This advisory is available at the following link:
This advisory is part of the September 2021 release of the Cisco IOS and
IOS XE Software Security Advisory Bundled Publication. For a complete list
of the advisories and links to them, see Cisco Event Response: September
2021 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled
o Vulnerable Products
This vulnerability affects Cisco EWC Software for Catalyst APs.
For information about which Cisco software releases are vulnerable, see the
Fixed Software section of this advisory.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory
are known to be affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect the following
Catalyst 9800 Series Wireless Controllers
IOS XR Software
Wireless LAN Controller (WLC) AireOS Software
Indicators of Compromise
o Exploitation of this vulnerability will cause the affected device to
generate the following log message:
Sep 22 16:00:00.000 UTC: %IOSXE_INFRA-3-GET_BUFFER_ERR: Interrupt processing of Punt received packets over socket failed to get a packet buffer for len
o There are no workarounds that address this vulnerability.
o Cisco has released free software updates that address the vulnerability
described in this advisory. Customers may only install and expect support
for software versions and feature sets for which they have purchased a
license. By installing, downloading, accessing, or otherwise using such
software upgrades, customers agree to follow the terms of the Cisco
Additionally, customers may only download software for which they have a
valid license, procured from Cisco directly, or through a Cisco authorized
reseller or partner. In most cases this will be a maintenance upgrade to
software that was previously purchased. Free security software updates do
not entitle customers to a new software license, additional software
feature sets, or major revision upgrades.
When considering software upgrades , customers are advised to regularly
consult the advisories for Cisco products, which are available from the
Cisco Security Advisories page , to determine exposure and a complete
In all cases, customers should ensure that the devices to be upgraded
contain sufficient memory and confirm that current hardware and software
configurations will continue to be supported properly by the new release.
If the information is not clear, customers are advised to contact the Cisco
Technical Assistance Center (TAC) or their contracted maintenance
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service
contract and customers who make purchases through third-party vendors but
are unsuccessful in obtaining fixed software through their point of sale
should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c
Customers should have the product serial number available and be prepared
to provide the URL of this advisory as evidence of entitlement to a free
Cisco IOS and IOS XE Software
To help customers determine their exposure to vulnerabilities in Cisco IOS
and IOS XE Software, Cisco provides the Cisco Software Checker to identify
any Cisco Security Advisories that impact a specific software release and
the earliest release that fixes the vulnerabilities described in each
advisory ("First Fixed"). If applicable, the tool also returns the earliest
release that fixes all the vulnerabilities described in all the advisories
identified ("Combined First Fixed").
Customers can use the Cisco Software Checker to search advisories in the
Choose the software and one or more releases
Upload a .txt file that includes a list of specific releases
Enter the output of the show version command
After initiating a search, customers can customize the search to include
all Cisco Security Advisories, a specific advisory, or all advisories in
the most recent bundled publication.
Customers can also use the following form to determine whether a release is
affected by any Cisco Security Advisory by entering a Cisco IOS or IOS XE
Software release-for example, 15.1(4)M2 or 3.13.8S :
By default, the Cisco Software Checker includes results only for
vulnerabilities that have a Critical or High Security Impact Rating (SIR).
To include results for Medium SIR vulnerabilities, customers can use the
Cisco Software Checker on Cisco.com and check the Medium check box in the
drop-down list under Impact Rating when customizing a search.
Exploitation and Public Announcements
o The Cisco Product Security Incident Response Team (PSIRT) is not aware of
any public announcements or malicious use of the vulnerability that is
described in this advisory.
o This vulnerability was found during internal security testing.
Cisco Security Vulnerability Policy
o To learn about Cisco security vulnerability disclosure policies and
publications, see the Security Vulnerability Policy . This document also
contains instructions for obtaining fixed software and receiving security
vulnerability information from Cisco.
Related to This Advisory
o Cisco Event Response: September 2021 Semiannual Cisco IOS and IOS XE
Software Security Advisory Bundled Publication
| Version | Description | Section | Status | Date |
| 1.0 | Initial public release. | - | Final | 2021-SEP-22 |
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