Is CVE-2021-34720 in the CISA KEV catalog?

No. CVE-2021-34720 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-34720?

CVE-2021-34720 has a CVSS v3 base score of 8.6 (HIGH).

What is the EPSS score for CVE-2021-34720?

CVE-2021-34720 has an EPSS score of 1.25% (66th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-34720?

Upgrade ios xr to 7.2.2 or later.

CVE & CISA-KEV Catalog

CVE-2021-34720

HIGH

8.6

CVSS v3

NVD

Description

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.

CWE-771

How to fix

Remediation Available

ios xrNVD

Affected:>= 6.5.0, < 7.2.2Fixed in:7.2.2CVE-2021-34720derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeChanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Exploit Intelligence

1.25%probability of exploitation in 30 days

66thpercentile

Moderate risk: more likely to be exploited than 66% of all known CVEs.

References

Vendor Advisory1

tools.cisco.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.