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CVE-2026-20349

HIGHCVSS 8.6/10Actively ExploitedEPSS 0.97%

Last modified

CVE-2026-20349 is a high-severity vulnerability rated 8.6/10 on the CVSS scale. A vulnerability in the Remote Access SSL VPN service for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition.  This vulnerability is due to insufficient error checking when processing HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to the Remote Access SSL VPN service on an affected device. CISA has confirmed active exploitation in the wild. EPSS estimates a 0.97% chance of exploitation in the next 30 days.

Description

A vulnerability in the Remote Access SSL VPN service for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition.  This vulnerability is due to insufficient error checking when processing HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to the Remote Access SSL VPN service on an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

Metrics

CVSS 3.1
8.6/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

EPSS Probability
0.97%

58.7th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by .

Weakness Enumeration

Affected Software

VendorProductVersions
CiscoAdaptive Security Appliance Software9.16.1
CiscoAdaptive Security Appliance Software9.16.1.28
CiscoAdaptive Security Appliance Software9.16.2
CiscoAdaptive Security Appliance Software9.16.2.3
CiscoAdaptive Security Appliance Software9.16.2.7
CiscoAdaptive Security Appliance Software9.16.2.11
CiscoAdaptive Security Appliance Software9.16.2.13
CiscoAdaptive Security Appliance Software9.16.2.14
CiscoAdaptive Security Appliance Software9.16.3
CiscoAdaptive Security Appliance Software9.16.3.3
CiscoAdaptive Security Appliance Software9.16.3.14
CiscoAdaptive Security Appliance Software9.16.3.15
CiscoAdaptive Security Appliance Software9.16.3.19
CiscoAdaptive Security Appliance Software9.16.3.23
CiscoAdaptive Security Appliance Software9.16.4
CiscoAdaptive Security Appliance Software9.16.4.9
CiscoAdaptive Security Appliance Software9.16.4.14
CiscoAdaptive Security Appliance Software9.16.4.19
CiscoAdaptive Security Appliance Software9.16.4.27
CiscoAdaptive Security Appliance Software9.16.4.38
CiscoAdaptive Security Appliance Software9.16.4.39
CiscoAdaptive Security Appliance Software9.16.4.42
CiscoAdaptive Security Appliance Software9.16.4.48
CiscoAdaptive Security Appliance Software9.16.4.55
CiscoAdaptive Security Appliance Software9.16.4.57
CiscoAdaptive Security Appliance Software9.16.4.61
CiscoAdaptive Security Appliance Software9.16.4.62
CiscoAdaptive Security Appliance Software9.16.4.67
CiscoAdaptive Security Appliance Software9.16.4.70
CiscoAdaptive Security Appliance Software9.16.4.71
CiscoAdaptive Security Appliance Software9.16.4.76
CiscoAdaptive Security Appliance Software9.16.4.82
CiscoAdaptive Security Appliance Software9.16.4.84
CiscoAdaptive Security Appliance Software9.16.4.85
CiscoAdaptive Security Appliance Software9.16.4.89
CiscoAdaptive Security Appliance Software9.16.4.92
CiscoAdaptive Security Appliance Software9.18.1
CiscoAdaptive Security Appliance Software9.18.1.3
CiscoAdaptive Security Appliance Software9.18.2
CiscoAdaptive Security Appliance Software9.18.2.5
CiscoAdaptive Security Appliance Software9.18.2.7
CiscoAdaptive Security Appliance Software9.18.2.8
CiscoAdaptive Security Appliance Software9.18.3
CiscoAdaptive Security Appliance Software9.18.3.39
CiscoAdaptive Security Appliance Software9.18.3.46
CiscoAdaptive Security Appliance Software9.18.3.53
CiscoAdaptive Security Appliance Software9.18.3.55
CiscoAdaptive Security Appliance Software9.18.3.56
CiscoAdaptive Security Appliance Software9.18.4
CiscoAdaptive Security Appliance Software9.18.4.5

Showing 50 of 197 affected configurations. See NVD for the full list.

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-20349?
A vulnerability in the Remote Access SSL VPN service for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition.  This vulnerability is due to insufficient error checking when processing HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to the Remote Access SSL VPN service on an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.
How severe is CVE-2026-20349?
CVE-2026-20349 has a CVSS score of 8.6/10 (HIGH severity). The EPSS model estimates a 0.97% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.
How do I fix CVE-2026-20349?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST