CVE-2021-34720 : A vulnerability in the IP Service Level Agreements (IP SLA) responder and Two-Wa

A vulnerability in the IP Service Level Agreements (IP SLA) responder and Two-Way Active Measurement Protocol (TWAMP) features of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause device packet memory to become exhausted or cause the IP SLA process to crash, resulting in a denial of service (DoS) condition. This vulnerability exists because socket creation failures are mishandled during the IP SLA and TWAMP processes. An attacker could exploit this vulnerability by sending specific IP SLA or TWAMP packets to an affected device. A successful exploit could allow the attacker to exhaust the packet memory, which will impact other processes, such as routing protocols, or crash the IP SLA process.

Published 2021-09-09 05:15:11

Updated 2022-10-25 18:04:49

Source Cisco Systems, Inc.

View at NVD, CVE.org

Vulnerability category: Denial of service

Products affected by CVE-2021-34720

Cisco » Ios Xr
Versions before (<) 6.2.3
cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*
Matching versions
When used together with: Cisco » Asr 9000v-v2 » Version: N/A
When used together with: Cisco » Asr 9001 » Version: N/A
When used together with: Cisco » Asr 9006 » Version: N/A
When used together with: Cisco » Asr 9010 » Version: N/A
When used together with: Cisco » Asr 9901 » Version: N/A
When used together with: Cisco » Asr 9902 » Version: N/A
When used together with: Cisco » Asr 9903 » Version: N/A
When used together with: Cisco » Asr 9904 » Version: N/A
When used together with: Cisco » Asr 9906 » Version: N/A
When used together with: Cisco » Asr 9910 » Version: N/A
When used together with: Cisco » Asr 9912 » Version: N/A
When used together with: Cisco » Asr 9922 » Version: N/A
Cisco » Ios Xr
Versions from including (>=) 6.5.0 and before (<) 7.2.2
cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*
Matching versions
When used together with: Cisco » Asr 9000v-v2 » Version: N/A
When used together with: Cisco » Asr 9001 » Version: N/A
When used together with: Cisco » Asr 9006 » Version: N/A
When used together with: Cisco » Asr 9010 » Version: N/A
When used together with: Cisco » Asr 9901 » Version: N/A
When used together with: Cisco » Asr 9902 » Version: N/A
When used together with: Cisco » Asr 9903 » Version: N/A
When used together with: Cisco » Asr 9904 » Version: N/A
When used together with: Cisco » Asr 9906 » Version: N/A
When used together with: Cisco » Asr 9910 » Version: N/A
When used together with: Cisco » Asr 9912 » Version: N/A
When used together with: Cisco » Asr 9922 » Version: N/A
Cisco » Ios Xr
Versions from including (>=) 6.3.0 and before (<) 6.3.2
cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*
Matching versions
When used together with: Cisco » Asr 9000v-v2 » Version: N/A
When used together with: Cisco » Asr 9001 » Version: N/A
When used together with: Cisco » Asr 9006 » Version: N/A
When used together with: Cisco » Asr 9010 » Version: N/A
When used together with: Cisco » Asr 9901 » Version: N/A
When used together with: Cisco » Asr 9902 » Version: N/A
When used together with: Cisco » Asr 9903 » Version: N/A
When used together with: Cisco » Asr 9904 » Version: N/A
When used together with: Cisco » Asr 9906 » Version: N/A
When used together with: Cisco » Asr 9910 » Version: N/A
When used together with: Cisco » Asr 9912 » Version: N/A
When used together with: Cisco » Asr 9922 » Version: N/A

Exploit prediction scoring system (EPSS) score for CVE-2021-34720

EPSS FAQ

1.02%

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

~ 75 %

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

CVSS scores for CVE-2021-34720

Base Score	Base Severity	CVSS Vector	Exploitability Score	Impact Score	Score Source
4.3	MEDIUM	AV:N/AC:M/Au:N/C:N/I:N/A:P	8.6	2.9	NIST
Access Vector: Network Access Complexity: Medium Authentication: None Confidentiality Impact: None Integrity Impact: None Availability Impact: Partial
8.6	HIGH	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H	3.9	4.0	Cisco Systems, Inc.
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: None Scope: Changed Confidentiality: None Integrity: None Availability: High
8.6	HIGH	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H	3.9	4.0	NIST
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: None Scope: Changed Confidentiality: None Integrity: None Availability: High

CWE ids for CVE-2021-34720

CWE-771 Missing Reference to Active Allocated Resource

The product does not properly maintain a reference to a resource that has been allocated, which prevents the resource from being reclaimed.

Assigned by: ykramarz@cisco.com (Secondary)

References for CVE-2021-34720

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ipsla-ZA3SRrpP

Cisco IOS XR Software IP Service Level Agreements and Two-Way Active Measurement Protocol Denial of Service Vulnerability
Vendor Advisory

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Vulnerability Details : CVE-2021-34720

Products affected by CVE-2021-34720

Exploit prediction scoring system (EPSS) score for CVE-2021-34720

CVSS scores for CVE-2021-34720

CWE ids for CVE-2021-34720

References for CVE-2021-34720