Is CVE-2021-34781 in the CISA KEV catalog?

No. CVE-2021-34781 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-34781?

CVE-2021-34781 has a CVSS v3 base score of 8.6 (HIGH).

What is the EPSS score for CVE-2021-34781?

CVE-2021-34781 has an EPSS score of 1.35% (68th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-34781?

Upgrade firepower threat defense to 7.0.1 or later.

CVE & CISA-KEV Catalog

CVE-2021-34781

HIGH

8.6

CVSS v3

NVD

Description

A vulnerability in the processing of SSH connections for multi-instance deployments of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on the affected device. This vulnerability is due to a lack of proper error handling when an SSH session fails to be established. An attacker could exploit this vulnerability by sending a high rate of crafted SSH connections to the instance. A successful exploit could allow the attacker to cause resource exhaustion, which causes a DoS condition on the affected device. The device must be manually reloaded to recover.

CWE-119Buffer Overflow CWE-755

How to fix

Remediation Available

firepower threat defenseNVD

Affected:>= 7.0.0, < 7.0.1Fixed in:7.0.1CVE-2021-34781derived 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

1.35%probability of exploitation in 30 days

68thpercentile

Moderate risk: more likely to be exploited than 68% of all known CVEs.

References

Vendor Advisory1

tools.cisco.com

Related Vulnerabilities

Other CWE-119 (Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-4966	Critical	9.4	100%	KEV + Ransom	Fix
CVE-2017-11882	High	7.8	100%	KEV + Ransom	-
CVE-2020-0796	Critical	10.0	100%	KEV + Ransom	-
CVE-2008-4250	Critical	9.8	99%	KEV	-
CVE-2017-15944	Critical	9.8	98%	KEV	Fix
CVE-2015-0014	High	10.0	97%	-	-

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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.