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Vulnerabilities / CVE-2026-20349

CVE-2026-20349

Published 2026-08-11 · Analyzed

CVE-2026-20349

Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection Vulnerability

Exploited in the wild: CISA added it to the Known Exploited Vulnerabilities catalog on 2026-08-11, with a fix-by date of 2026-08-14. Patch it first.

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.

8.6 HIGH
CVSS 3.1 · CNA · cisco.com
1.0%
chance of exploitation in the next 30 days (EPSS; higher than 63% of CVEs)

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.

Scores

Affected products

  • cisco adaptive security appliance software: 133 specific releases listed in NVD
  • cisco secure firewall threat defense: 64 specific releases listed in NVD

Weakness: CWE-244

2 references (advisories, patches, write-ups)

Sources: NVD, CVE.org, FIRST EPSS. Missing ones did not answer or have no record yet.

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