CVE-2022-20946
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.95%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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. This vulnerability is due to a memory handling error that occurs when GRE traffic is processed. An attacker could exploit this vulnerability by sending a crafted GRE payload through an affected device. A successful exploit could allow the attacker to cause the device to restart, resulting in a DoS condition. https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-gre-dos-hmedHQPM ["https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-gre-dos-hmedHQPM"] This advisory is part of the November 2022 release of the Cisco ASA, FTD, and FMC Security Advisory Bundled publication.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.95% probability · 61th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-122, CWE-787
- Affected
- cisco/secure firewall threat defense
- Source
- psirt@cisco.com
EPSS 0.9% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.