-----BEGIN PGP SIGNED MESSAGE-----
AUSCERT External Security Bulletin Redistribution
Cisco Webex Room Phone and Cisco Webex Share Link Layer
Discovery Protocol Memory Leak Vulnerability
12 January 2023
AusCERT Security Bulletin Summary
Product: Cisco Webex Room Phone
Cisco Webex Share Link Layer Discovery Protocol
Publisher: Cisco Systems
Operating System: Cisco
CVE Names: CVE-2023-20047
Comment: CVSS (Max): 6.5 CVE-2023-20047 (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
CVSS Source: Cisco Systems
- --------------------------BEGIN INCLUDED TEXT--------------------
Cisco Webex Room Phone and Cisco Webex Share Link Layer Discovery Protocol
Memory Leak Vulnerability
Advisory ID: cisco-sa-lldp-memlk-McOecPT
First Published: 2023 January 11 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds available
Cisco Bug IDs: CSCwb22136 CSCwb25580
CVE Names: CVE-2023-20047
o A vulnerability in the Link Layer Discovery Protocol (LLDP) feature of
Cisco Webex Room Phone and Cisco Webex Share devices could allow an
unauthenticated, adjacent attacker to cause a denial of service (DoS)
condition on an affected device.
This vulnerability is due to insufficient resource allocation. An attacker
could exploit this vulnerability by sending crafted LLDP traffic to an
affected device. A successful exploit could allow the attacker to exhaust
the memory resources of the affected device, resulting in a crash of the
LLDP process. If the affected device is configured to support LLDP only,
this could cause an interruption to inbound and outbound calling. By
default, these devices are configured to support both Cisco Discovery
Protocol and LLDP. To recover operational state, the affected device needs
a manual restart.
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:
o Vulnerable Products
At the time of publication, this vulnerability affected the following Cisco
products if they were running a vulnerable release of firmware and had the
LLDP feature enabled. The LLDP feature is enabled by default.
Webex Room Phone
For information about which Cisco software releases were vulnerable at the
time of publication, see the Fixed Software section of this advisory. See
the Details section in the bug ID(s) at the top of this advisory for the
most complete and current information.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory
are known to be affected by this vulnerability.
o There are no workarounds that address this vulnerability. However, there is
a mitigation that addresses this vulnerability for deployments that support
both Cisco Discovery Protocol and LLDP for neighbor discovery.
Administrators may disable LLDP on affected devices. Devices will then use
Cisco Discovery Protocol for discovery of configuration data such as voice
VLAN, power negotiation, and so on. This is not a trivial change and will
require diligence on behalf of the enterprise to evaluate any potential
impact to devices as well as the best approach to deploy this change in
While this mitigation has been deployed and was proven successful in a test
environment, customers should determine the applicability and effectiveness
in their own environment and under their own use conditions. Customers
should be aware that any workaround or mitigation that is implemented may
negatively impact the functionality or performance of their network based
on intrinsic customer deployment scenarios and limitations. Customers
should not deploy any workarounds or mitigations before first evaluating
the applicability to their own environment and any impact to such
o 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
At the time of publication, the release information in the following tables
was accurate. See the Details section in the bug ID(s) at the top of this
advisory for the most complete and current information.
The left column lists Cisco software releases, and the right column
indicates whether a release was affected by the vulnerability that is
described in this advisory and which release included the fix for this
Cisco Webex Room Phone and Cisco Webex Share Firmware First Fixed
1.2.0 and earlier 1.2.0SR3
The Cisco Product Security Incident Response Team (PSIRT) validates only
the affected and fixed release information that is documented in this
Exploitation and Public Announcements
o The Cisco PSIRT is not aware of any public announcements or malicious use
of the vulnerability that is described in this advisory.
o Cisco would like to thank Qian Chen of the Codesafe Team of Legendsec at
QI-ANXIN Group for reporting this vulnerability.
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.
Subscribe to Cisco Security Notifications
Related to This Advisory
| Version | Description | Section | Status | Date |
| 1.0 | Initial public release. | - | Final | 2023-JAN-11 |
o THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND
OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT
OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES
THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A standalone copy or paraphrase of the text of this document that omits the
distribution URL is an uncontrolled copy and may lack important information
or contain factual errors. The information in this document is intended for
end users of Cisco products.
- --------------------------END INCLUDED TEXT--------------------
You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to email@example.com
and we will forward your request to the appropriate person.
NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members. As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.
NOTE: This is only the original release of the security bulletin. It may
not be updated when updates to the original are made. If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.
Contact information for the authors of the original document is included
in the Security Bulletin above. If you have any questions or need further
information, please contact them directly.
Previous advisories and external security bulletins can be retrieved from:
Australian Computer Emergency Response Team
The University of Queensland
Internet Email: firstname.lastname@example.org
Facsimile: (07) 3365 7031
Telephone: (07) 3365 4417 (International: +61 7 3365 4417)
AusCERT personnel answer during Queensland business hours
which are GMT+10:00 (AEST).
On call after hours for member emergencies only.
-----BEGIN PGP SIGNATURE-----
-----END PGP SIGNATURE-----