CVE-2026-20349

CVE-2026-20349 is a high-severity vulnerability in Cisco Adaptive Security Appliance Software with a CVSS 3.x base score of 8.6. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2026-08-11). The underlying weakness is classified as CWE-244.

Key facts

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.

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 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-20349 being actively exploited?
Yes. CVE-2026-20349 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-08-11, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2026-20349?
CVE-2026-20349 primarily affects Cisco Adaptive Security Appliance Software. In total, 197 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-20349?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
When was CVE-2026-20349 published?
CVE-2026-20349 was published on 2026-08-11 and last updated on 2026-08-12.

References

Affected products (197)

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