CVE-2021-34696 : A vulnerability in the access control list (ACL) programming of Cisco ASR 900 an

A vulnerability in the access control list (ACL) programming of Cisco ASR 900 and ASR 920 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to bypass a configured ACL. This vulnerability is due to incorrect programming of hardware when an ACL is configured using a method other than the configuration CLI. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to bypass an ACL on the affected device.

Published 2021-09-23 03:15:16

Updated 2021-10-05 17:48:49

Source Cisco Systems, Inc.

View at NVD, CVE.org

Vulnerability category: BypassGain privilege

Products affected by CVE-2021-34696

Cisco » Ios Xe
Versions up to, including, (<=) 17.3.2
cpe:2.3:o:cisco:ios_xe:*:*:*:*:*:*:*:*
Matching versions
When used together with: Cisco » Asr 902 » Version: N/A
When used together with: Cisco » Asr 903 » Version: N/A
When used together with: Cisco » Asr 907 » Version: N/A
When used together with: Cisco » Asr 920-10sz-pd » Version: N/A
When used together with: Cisco » Asr 920-10sz-pd R » Version: N/A
When used together with: Cisco » Asr 920-12cz-a » Version: N/A
When used together with: Cisco » Asr 920-12cz-a R » Version: N/A
When used together with: Cisco » Asr 920-12cz-d » Version: N/A
When used together with: Cisco » Asr 920-12cz-d R » Version: N/A
When used together with: Cisco » Asr 920-12sz-im » Version: N/A
When used together with: Cisco » Asr 920-12sz-im R » Version: N/A
When used together with: Cisco » Asr 920-24sz-im » Version: N/A
When used together with: Cisco » Asr 920-24sz-im R » Version: N/A
When used together with: Cisco » Asr 920-24sz-m » Version: N/A
When used together with: Cisco » Asr 920-24sz-m R » Version: N/A
When used together with: Cisco » Asr 920-24tz-m » Version: N/A
When used together with: Cisco » Asr 920-24tz-m R » Version: N/A
When used together with: Cisco » Asr 920-4sz-a » Version: N/A
When used together with: Cisco » Asr 920-4sz-a R » Version: N/A
When used together with: Cisco » Asr 920-4sz-d » Version: N/A
When used together with: Cisco » Asr 920-4sz-d R » Version: N/A
When used together with: Cisco » Asr 920u-12sz-im » Version: N/A

Exploit prediction scoring system (EPSS) score for CVE-2021-34696

EPSS FAQ

0.26%

Probability of exploitation activity in the next 30 days EPSS Score History

~ 47 %

Percentile, the proportion of vulnerabilities that are scored at or less

CVSS scores for CVE-2021-34696

Base Score	Base Severity	CVSS Vector	Exploitability Score	Impact Score	Score Source
5.0	MEDIUM	AV:N/AC:L/Au:N/C:N/I:P/A:N	10.0	2.9	NIST
Access Vector: Network Access Complexity: Low Authentication: None Confidentiality Impact: None Integrity Impact: Partial Availability Impact: None
5.8	MEDIUM	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N	3.9	1.4	Cisco Systems, Inc.
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: None Scope: Changed Confidentiality: None Integrity: Low Availability: None
5.8	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N	3.9	1.4	NIST
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: None Scope: Changed Confidentiality: None Integrity: Low Availability: None

CWE ids for CVE-2021-34696

CWE-284 Improper Access Control

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

Assigned by: ykramarz@cisco.com (Secondary)

References for CVE-2021-34696

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asr900acl-UeEyCxkv

Cisco ASR 900 and ASR 920 Series Aggregation Services Routers Access Control List Bypass Vulnerability
Vendor Advisory

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Vulnerability Details : CVE-2021-34696

Products affected by CVE-2021-34696

Exploit prediction scoring system (EPSS) score for CVE-2021-34696

CVSS scores for CVE-2021-34696

CWE ids for CVE-2021-34696

References for CVE-2021-34696