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AUSCERT External Security Bulletin Redistribution
Cisco IOS XE Software Web UI Command Injection Vulnerability
29 September 2022
AusCERT Security Bulletin Summary
Product: Cisco IOS XE
Publisher: Cisco Systems
Operating System: Cisco
CVE Names: CVE-2022-20851
Comment: CVSS (Max): 5.5 CVE-2022-20851 (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:H/A:N)
CVSS Source: Cisco Systems
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Cisco IOS XE Software Web UI Command Injection Vulnerability
Advisory ID: cisco-sa-webui-cmdinj-Gje47EMn
First Published: 2022 September 28 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds available
Cisco Bug IDs: CSCvz74822
CVE Names: CVE-2022-20851
o A vulnerability in the web UI feature of Cisco IOS XE Software could allow
an authenticated, remote attacker to perform an injection attack against an
This vulnerability is due to insufficient input validation. An attacker
could exploit this vulnerability by sending crafted input to the web UI
API. A successful exploit could allow the attacker to execute arbitrary
commands on the underlying operating system with root privileges. To
exploit this vulnerability, an attacker must have valid Administrator
privileges on the affected device.
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 2022 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
2022 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled
o Vulnerable Products
At the time of publication, this vulnerability affected Cisco products if
they were running a vulnerable release of Cisco IOS XE Software and had the
web UI feature enabled.
For information about which Cisco software releases are vulnerable, see the
Fixed Software section of this advisory.
Determine the HTTP Server Configuration
To determine whether the HTTP Server feature is enabled for a device, log
in to the device and use the show running-config | include ip http server|
secure|active command in the CLI to check for the presence of the ip http
server command or the ip http secure-server command in the global
configuration. If either command is present, the HTTP Server feature is
enabled for the device.
The following example shows the output of the show running-config | include
ip http server|secure|active command for a device that has the HTTP Server
Router# show running-config | include ip http server|secure|active
ip http server
ip http secure-server
Note: The presence of either command or both commands in the device
configuration indicates that the web UI feature is enabled.
If the ip http server command is present and the configuration also
contains ip http active-session-modules none , the vulnerability is not
exploitable over HTTP.
If the ip http secure-server command is present and the configuration also
contains ip http secure-active-session-modules none , the vulnerability is
not exploitable over HTTPS.
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
IOS XR Software
o There are no workarounds that address this vulnerability.
Disabling the HTTP Server feature eliminates the attack vector for this
vulnerability and may be a suitable mitigation until affected devices can
be upgraded. To disable the HTTP Server feature, use the no ip http server
or no ip http secure-server command in global configuration mode. If both
the HTTP server and HTTPS server are in use, both commands are required to
disable the HTTP Server feature.
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
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 . This tool
identifies any Cisco security advisories that impact a specific software
release and the earliest release that fixes the vulnerabilities that are
described in each advisory ("First Fixed"). If applicable, the tool also
returns the earliest release that fixes all the vulnerabilities that are
described in all the advisories that the Software Checker identifies
("Combined First Fixed").
To use the tool, go to the Cisco Software Checker page and follow the
instructions. Alternatively, use the following form to determine whether a
release is affected by any Cisco Security Advisory. To use the form, follow
1. Choose which advisories the tool will search-only this advisory, only
advisories with a Critical or High Security Impact Rating (SIR) , or
2. Enter a release number-for example, 15.9(3)M2 or 17.3.3.
3. Click Check
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 2022 Semiannual Cisco IOS and IOS XE
Software Security Advisory Bundled Publication
| Version | Description | Section | Status | Date |
| 1.0 | Initial public release. | - | Final | 2022-SEP-28 |
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