CVE-2026-20295: Memory Allocation with Excessive Size Value in Cisco Cisco Secure Firewall Management Center (FMC)
A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software and Cisco Secure FTD Software could allow an unauthenticated, remote attacker to exhaust the available memory of an affected device. This vulnerability is due to improper management of memory resources during sftunnel TLS connection setup. An attacker could exploit this vulnerability by sending crafted sftunnel TLS frames to an affected device during the connection setup. A successful exploit could allow the attacker to exhaust the available memory on the affected device, which could result in a DoS condition.
AI Analysis
Technical Summary
This vulnerability arises from improper handling of memory resources in the sftunnel inter-device communication protocol during TLS connection setup in Cisco Secure FMC and FTD Software. An unauthenticated remote attacker can exploit this by sending specially crafted sftunnel TLS frames, causing the affected device to exhaust its available memory. This leads to a denial-of-service condition, impacting device availability. The CVSS v3.1 base score is 8.6, reflecting high severity with network attack vector, low attack complexity, no privileges or user interaction required, and impact limited to availability.
Potential Impact
Exploitation results in exhaustion of available memory on the affected device, causing a denial-of-service condition. There is no impact on confidentiality or integrity reported. The affected devices may become unresponsive or fail to operate correctly due to memory depletion.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch links are provided in the available data. Until a patch is available, monitor Cisco advisories for updates and consider limiting exposure of the sftunnel service to untrusted networks if possible.
CVE-2026-20295: Memory Allocation with Excessive Size Value in Cisco Cisco Secure Firewall Management Center (FMC)
Description
A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software and Cisco Secure FTD Software could allow an unauthenticated, remote attacker to exhaust the available memory of an affected device. This vulnerability is due to improper management of memory resources during sftunnel TLS connection setup. An attacker could exploit this vulnerability by sending crafted sftunnel TLS frames to an affected device during the connection setup. A successful exploit could allow the attacker to exhaust the available memory on the affected device, which could result in a DoS condition.
CVSS v3.1
Score 8.6high
Affected software
Cisco
Cisco Secure Firewall Management Center (FMC)
Cisco
Cisco Secure Firewall Threat Defense (FTD) Software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability arises from improper handling of memory resources in the sftunnel inter-device communication protocol during TLS connection setup in Cisco Secure FMC and FTD Software. An unauthenticated remote attacker can exploit this by sending specially crafted sftunnel TLS frames, causing the affected device to exhaust its available memory. This leads to a denial-of-service condition, impacting device availability. The CVSS v3.1 base score is 8.6, reflecting high severity with network attack vector, low attack complexity, no privileges or user interaction required, and impact limited to availability.
Potential Impact
Exploitation results in exhaustion of available memory on the affected device, causing a denial-of-service condition. There is no impact on confidentiality or integrity reported. The affected devices may become unresponsive or fail to operate correctly due to memory depletion.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch links are provided in the available data. Until a patch is available, monitor Cisco advisories for updates and consider limiting exposure of the sftunnel service to untrusted networks if possible.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- cisco
- Date Reserved
- 2025-10-08T11:59:15.405Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6aab006a55bf5e2cf5232014
Added to database: 09/16/2026, 20:47:38 UTC
Last enriched: 09/16/2026, 21:18:24 UTC
Last updated: 09/17/2026, 04:01:23 UTC
Views: 6
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