Is CVE-2021-34793 in the CISA KEV catalog?

No. CVE-2021-34793 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-34793?

CVE-2021-34793 has a CVSS v3 base score of 8.6 (HIGH).

What is the EPSS score for CVE-2021-34793?

CVE-2021-34793 has an EPSS score of 0.65% (47th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-34793?

Upgrade adaptive security appliance to 9.8.4.40 or later. Fixes are available for 3 affected products.

CVE & CISA-KEV Catalog

CVE-2021-34793

HIGH

8.6

CVSS v3

NVD

Description

A vulnerability in the TCP Normalizer of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software operating in transparent mode could allow an unauthenticated, remote attacker to poison MAC address tables, resulting in a denial of service (DoS) vulnerability. This vulnerability is due to incorrect handling of certain TCP segments when the affected device is operating in transparent mode. An attacker could exploit this vulnerability by sending a crafted TCP segment through an affected device. A successful exploit could allow the attacker to poison the MAC address tables in adjacent devices, resulting in network disruption.

CWE-924

How to fix

Remediation Available

adaptive security applianceNVD

Affected:< 9.8.4.40Fixed in:9.8.4.40CVE-2021-34793derived from NVD

adaptive security appliance softwareNVD

Affected:>= 9.16.0, < 9.16.2.3Fixed in:9.16.2.3CVE-2021-34793derived from NVD

firepower threat defenseNVD

Affected:>= 6.7.0, < 6.7.0.3Fixed in:6.7.0.3CVE-2021-34793derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

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

0.65%probability of exploitation in 30 days

47thpercentile

Moderate risk: more likely to be exploited than 47% of all known CVEs.

References

Vendor Advisory1

tools.cisco.com

Related Vulnerabilities

Other CWE-924 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-3596	Critical	9.0	15%	-	Fix
CVE-2018-14526	Medium	6.5	1.5%	-	Fix
CVE-2021-21390	Medium	6.5	0.9%	-	Fix
CVE-2022-3166	High	7.5	0.7%	-	-
CVE-2021-3716	Low	3.1	0.6%	-	Fix
CVE-2024-43450	High	7.5	0.6%	-	Fix

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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.