CVE-2021-34720: high-severity vulnerability in Cisco IOS XR Software
Cisco IOS XR Software IP Service Level Agreements and Two-Way Active Measurement Protocol Denial of Service Vulnerability
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.6epss 1.3%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Affected products
Cisco · Cisco IOS XR SoftwareRelated CVEs — Cisco IOS XR Software
In the same product, most dangerous first.
CVE-2020-3118HIGHCisco IOS XR Software Cisco Discovery Protocol Format String VulnerabilityEPSS 11.7%KEVCVE-2022-20821MEDIUMCisco IOS XR Software Health Check Open Port VulnerabilityEPSS 11.5%KEVCVE-2020-3566HIGHCisco IOS XR Software DVMRP Memory Exhaustion VulnerabilityEPSS 3.7%KEVCVE-2020-3569HIGHCisco IOS XR Software DVMRP Memory Exhaustion VulnerabilitiesEPSS 3.3%KEVCVE-2025-20363CRITICALCVE-2025-20363EPSS 7.2%CVE-2020-3284HIGHCisco IOS XR Software Enhanced Preboot eXecution Environment Unsigned Code Execution VulnerabilityEPSS 2.9%