Description
A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker to execute arbitrary code on an affected device.
This vulnerability is due to improper validation of user-supplied input in HTTP(S) requests. An attacker with valid VPN user credentials could exploit this vulnerability by sending crafted HTTP requests to an affected device. A successful exploit could allow the attacker to execute arbitrary code as root, possibly resulting in the complete compromise of the affected device.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Cisco | Cisco Secure Firewall Adaptive Security Appliance (ASA) Software | 9.8.1, 9.8.1.5, 9.8.1.7, 9.8.2, 9.8.2.8, 9.8.2.14, 9.8.2.15, 9.8.2.17, 9.8.2.20, 9.8.2.24, 9.8.2.26, 9.8.2.28, 9.8.2.33, 9.8.2.35, 9.8.2.38, 9.8.3.8, 9.8.3.11, 9.8.3.14, 9.8.3.16, 9.8.3.18, 9.8.3.21, 9.8.3, 9.8.3.26, 9.8.3.29, 9.8.4, 9.8.4.3, 9.8.4.7, 9.8.4.8, 9.8.4.10, 9.8.4.12, 9.8.4.15, 9.8.4.17… | — |
| Cisco | Cisco Secure Firewall Threat Defense (FTD) Software | 6.2.3, 6.2.3.1, 6.2.3.2, 6.2.3.3, 6.2.3.4, 6.2.3.5, 6.2.3.6, 6.2.3.7, 6.2.3.8, 6.2.3.10, 6.2.3.11, 6.2.3.9, 6.2.3.12, 6.2.3.13, 6.2.3.14, 6.2.3.15, 6.2.3.16, 6.2.3.17, 6.2.3.18, 6.6.0, 6.6.0.1, 6.6.1, 6.6.3, 6.6.4, 6.6.5, 6.6.5.1, 6.6.5.2, 6.6.7, 6.6.7.1, 6.6.7.2, 6.4.0, 6.4.0.1, 6.4.0.3, 6.4.0.2, … | — |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
GitHub 3 repositories
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cobbbex/cve-2025-20333 ★ 0 · Aug 31, 2026
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cobbbex/Cisco-ASA-vulnerability-research ★ 0 · Aug 22, 2026
Cisco ASA vulnerability research CVE-2025-20333/CVE-2025-20362
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curtishoughton/Cisco-ASA-CVE-2025-20333-Scanner ★ 0 · May 16, 2026
Safe Python scanner for Cisco CVE-2025-20333 (Cisco ASA/FTD WebVPN Buffer Overflow)
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 2
- WID-SEC-2025-2142 Cisco ASA, FTD, IOS, IOS XE, IOS XR: Mehrere Schwachstellen BSI CERT-Bund (WID) · Apr 23, 2026
- NCSC-2025-0298 Kwetsbaarheden verholpen in Cisco Secure Firewall ASA en FTD NCSC-NL (Netherlands) · Sep 25, 2025