CVE-2026-20049
Cisco Secure Firewall Adaptive Security Appliance and FTD Denial of Service Vulnerability in GCM-Encrypted IKEv2 IPsec Traffic Processing
Description
A vulnerability in the processing of Galois/Counter Mode (GCM)-encrypted Internet Key Exchange version 2 (IKEv2) IPsec traffic of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to the allocation of an insufficiently sized block of memory. An attacker could exploit this vulnerability by sending crafted GCM-encrypted IPsec traffic to an affected device. A successful exploit could allow the attacker to cause an unexpected reload of the device, resulting in a DoS condition. To exploit this vulnerability, the attacker must have valid credentials to establish a VPN connection with the affected device.
INFO
Published Date :
March 4, 2026, 6:16 p.m.
Last Modified :
March 5, 2026, 7:39 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-20049
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | MITRE-CVE |
Solution
- Update Cisco Secure Firewall ASA Software to the latest version.
- Update Cisco Secure Firewall FTD Software to the latest version.
- Apply vendor-provided patches promptly.
- Monitor network traffic for suspicious IPsec activity.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-20049.
| URL | Resource |
|---|---|
| https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-esp-dos-uv7yD8P5 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-20049 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-20049
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-20049 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-20049 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Mar. 04, 2026
Action Type Old Value New Value Added Description A vulnerability in the processing of Galois/Counter Mode (GCM)-encrypted Internet Key Exchange version 2 (IKEv2) IPsec traffic of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to the allocation of an insufficiently sized block of memory. An attacker could exploit this vulnerability by sending crafted GCM-encrypted IPsec traffic to an affected device. A successful exploit could allow the attacker to cause an unexpected reload of the device, resulting in a DoS condition. To exploit this vulnerability, the attacker must have valid credentials to establish a VPN connection with the affected device. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H Added CWE CWE-131 Added Reference https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-esp-dos-uv7yD8P5