Is CVE-2021-1616 in the CISA KEV catalog?

No. CVE-2021-1616 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-1616?

CVE-2021-1616 has a CVSS v3 base score of 4.7 (MEDIUM).

What is the EPSS score for CVE-2021-1616?

CVE-2021-1616 has an EPSS score of 1.16% (63th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-1616?

Upgrade ios xe to 17.6.1 or later.

CVE & CISA-KEV Catalog

CVE-2021-1616

MEDIUM

4.7

CVSS v3

NVD

Description

A vulnerability in the H.323 application level gateway (ALG) used by the Network Address Translation (NAT) feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to bypass the ALG. This vulnerability is due to insufficient data validation of traffic that is traversing the ALG. An attacker could exploit this vulnerability by sending crafted traffic to a targeted device. A successful exploit could allow the attacker to bypass the ALG and open connections that should not be allowed to a remote device located behind the ALG. Note: This vulnerability has been publicly discussed as NAT Slipstreaming.

CWE-693Protection Mechanism Failure

How to fix

Remediation Available

ios xeNVD

Affected:< 17.6.1Fixed in:17.6.1CVE-2021-1616derived 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 InteractionRequired

ScopeChanged

Impact

ConfidentialityNone

IntegrityLow

AvailabilityNone

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

Exploit Intelligence

1.16%probability of exploitation in 30 days

63rdpercentile

Moderate risk: more likely to be exploited than 63% 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.