CVE-2026-20052 Cisco Secure Firewall Threat Defense Software Snort 3 Memory Management Denial of Service Vulnerability
An unauthenticated remote attacker can cause a denial of service by sending crafted SSL packets to the Snort 3 Detection Engine, requiring SSL inspection to be enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-20052?
CVE-2026-20052 is a medium-severity denial of service vulnerability in Cisco Secure Firewall Threat Defense, published on 4 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability in the memory management handling for the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart. This vulnerability is due to a logic error in memory management when a device is performing Snort 3 SSL packet inspection. An attacker could exploit this vulnerability by sending crafted SSL packets through an established connection to be parsed by the Snort 3 Detection Engine. A successful exploit could allow the attacker to cause a denial of service (DoS) condition when the Snort 3 Detection Engine unexpectedly restarts.
Weakness: CWE-788
Which versions are affected by CVE-2026-20052?
It affects 1 product.
Products include Cisco Secure Firewall Threat Defense.
How do I fix CVE-2026-20052?
No fix has been published for CVE-2026-20052 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-20052 being exploited?
There is no known exploitation of CVE-2026-20052 in the wild and no public exploit code.
Other vulnerabilities in Cisco Secure Firewall Threat Defense
- CVE-2024-20412 Hardcoded credentials in Cisco Firepower Threat Defense Software
- CVE-2024-20330 Memory corruption in Cisco Firepower Threat Defense Software
- CVE-2024-20339 Cisco Firepower Threat Defense Software for Firepower 2100 Series TLS Denial of Service Vulnerability
- CVE-2024-20351 Cisco Firepower Threat Defense Software Snort Firewall Denial of Service Vulnerability
- CVE-2023-20083 Denial of service in Cisco Firepower Threat Defense Software
Sources
Also known as GHSA-f3x2-jxv4-r583.