Vulnerability in Cisco Adaptive Security Appliance Software
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.010 (61.6th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 62nd percentile — 61.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.022 · newest: 0.010 · change: -0.012
Affected products
- Cisco Adaptive Security Appliance Software — versions 9.16.1, 9.16.1.28, 9.16.2
- Cisco Secure Firewall Adaptive Security Appliance (Asa) Software — versions 9.18.4.71, 9.16.4.70, 9.22.2.4
- Cisco Secure Firewall Threat Defense (Ftd) Software — versions 7.0.0, 7.0.0.1, 7.0.1
- Cisco Secure Firewall Threat Defense — versions 7.0.0, 7.0.0.1, 7.0.1
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
References
- sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-… (Vendor Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)
Frequently asked questions
- What is CVE-2026-20349?
- CVE-2026-20349 is a high-severity vulnerability in Cisco Adaptive Security Appliance Software, classified under CWE-244. CVSS score: 8.6/10. Published 2026-08-11.
- How severe is CVE-2026-20349?
- High severity. CVSS v3 base score is 8.6 out of 10.
- Is CVE-2026-20349 known to be exploited?
- Yes. CVE-2026-20349 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-08-11), indicating it is being actively exploited.