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Fencer Intel
high 8.6

CVE-2020-3179 json

Cisco Firepower Threat Defense Software Generic Routing Encapsulation Tunnel IPv6 Denial of Service Vulnerability

published 6y ago modified 2mo ago also EUVD-2020-24450

cvss
8.6
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.0%
EPSS 2.0% chance of exploitation in 30 days, percentile 80%
public exploits
0
none known

Summary

A vulnerability in the generic routing encapsulation (GRE) tunnel decapsulation feature of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a memory handling error when GRE over IPv6 traffic is processed. An attacker could exploit this vulnerability by sending crafted GRE over IPv6 packets with either IPv4 or IPv6 payload through an affected device. A successful exploit could allow the attacker to cause the device to crash, resulting in a DoS condition.

Patch / fix

  • cisco secure_firewall_threat_defense 6.3.0.5, 6.4.0.6

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
last yr.

Exploit prediction

2.00% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.0 8.6 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 7.8 AV:N/AC:L/Au:N/C:N/I:N/A:C

Affected products

  • Cisco Cisco Firepower Threat Defense Software

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.