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CVE-2020-3571

27
FAUCET Score

CVE-2020-3571 is a denial-of-service vulnerability in Cisco Firepower Threat Defense (FTD) Software for Firepower 4100 Series appliances, caused by incomplete input validation of ICMP packets. An unauthenticated, remote attacker can exploit this by sending a high volume of crafted ICMP or ICMPv6 packets, leading to memory exhaustion and an unexpected device reload. Rated 8.6 HIGH (CVSSv3.1), this vulnerability requires no user interaction and has a high impact on availability. There is no evidence of active exploitation, public exploit code, or significant community discussion.

Impacted Technologies

VendorProductVersion(s)CPE
>= 6.3.0, < 6.3.0.6CPE matchmatch criteria
cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:*
>= 6.4.0, < 6.4.0.10CPE matchmatch criteria
cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:*
>= 6.5.0, < 6.5.0.5CPE matchmatch criteria
cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

8.6HIGH

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
4.0
CvssVersion
3.0

Exploit Intelligence

EPSS Score
1.37%
Probability of exploitation in next 30 days
EPSS Percentile
69.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0137 is in the 50th percentile among its peer group of 51,551 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (1)

ciscovendor investigatingvia nvd_reference
View patch

References

tools.cisco.com / security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-icmp-dos-hxxcycM
Vendor Advisory