Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection Vulnerability
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…
Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.
Exploitation probability EPSS · FIRST
Exploitation signals 3 / 5
- KEV catalog (CISA)11 Aug 2026
- Exploited in EUVD (ENISA)11 Aug 2026
- Used by ransomwareno
- EPSS above 10 %1.0%
- No account, over the networkyes
What to do
Fix
Apply the vendor’s fix as soon as it is available.
CISA guidance: 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.
Meanwhile
Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.
Manufacturers (CRA)
Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained
Description ENISA EUVD
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.
Affected products
- 9.22.2.9
- 7.2.4.1
- 9.20.4.28
- 9.18.4.52
- 9.24.1.11
- 9.16.2.3
- 7.0.5
- 9.16.2.13
- 9.16.4.62
- 9.22.3.5
- 9.16.4.82
- 9.19.1
Open source packages OSV
Affected libraries according to OSV, with fixed versions.
Timeline
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Published
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Exploitation reported (ENISA)
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Added to the KEV catalog
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CISA remediation due date
References
Other exploited vulnerabilities from the same vendor
- CVE-2026-76418Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability5.3 · Rising fast
- CVE-2026-76519Cisco Secure Email Gateway Relative Path Traversal Vulnerability5.8 · Rising fast
- CVE-2026-76504Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability7.5 · Actively exploited
- CVE-2026-76460Cisco Identity Services Engine Incorrect Use of Privileged APIs Vulnerability8.7 · Actively exploited
- CVE-2026-76461Cisco Secure Email Gateway SQL Injection Vulnerability7.2 · Actively exploited
- CVE-2026-20079Cisco Firewall Management Center Authentication Bypass Using an Alternate Path or Channel Vulnerability9.1 · Actively exploited