SB20260917234 - Multiple vulnerabilities in Cisco Secure Firewall Threat Defense
Published: September 17, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 2 vulnerabilities.
1) Buffer Access with Incorrect Length Value (CVE-ID: CVE-2026-20290)
CWE-ID: CWE-805 - Buffer Access with Incorrect Length Value
CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to incomplete validation in SSL/TLS certificate parsing in the Snort 2 Detection Engine. A remote attacker can send a specially crafted SSL connection setup request and cause a denial of service condition on the target system.
2) Double free (CVE-ID: CVE-2026-20135)
CWE-ID: CWE-415 - Double Free
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a boundary error in the TLS 1.3 implementation. A remote attacker can send a specially crafted TLS 1.3 packet, trigger double free error and causea denial of service condition on the target system.
Remediation
Install update from vendor's website.