Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense…
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
A vulnerability in the DNS over TCP implementation of 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 TCP DNS response handler to unexpectedly restart, causing the device to reload. This vulnerability is due to a logic error when parsing a DNS query and tracking the size of the incoming buffers. An attacker could exploit this vulnerability by formatting a crafted reply to a DNS query sent from the targeted device. A successful exploit could allow the attacker to cause the device to reload, causing a denial of service (DoS) condition. Note: The attacker must be able to respond to DNS queries from the device, either by controlling the DNS service or through a machine-in-the-middle attack.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Cisco | Cisco Secure Firewall Adaptive Security Appliance (ASA) Software | 9.16.1; 9.16.1.28; 9.16.2; 9.16.2.3; 9.16.2.7; 9.16.2.11; 9.16.2.13; 9.16.2.14; 9.16.3.3; 9.16.3; 9.16.3.14; 9.18.1; 9.16.3.15; 9.18.1.3; 9.18.2; 9.16.3.19; 9.16.3.23; 9.18.2.5; 9.16.4; 9.18.2.7; 9.19.1; 9.16.4.9; 9.18.2.8; 9.16.4.14; 9.18.3; 9.19.1.5; 9.16.4.18; 9.19.1.9; 9.18.3.39; 9.16.4.19; 9.19.1.12; 9.18.3.46; 9.16.4.27; 9.19.1.18; 9.18.3.53; 9.18.3.55; 9.16.4.38; 9.16.4.39; 9.18.3.56; 9.20.1; 9.16.4.42; 9.19.1.22; 9.18.4; 9.20.1.5; 9.18.4.5; 9.19.1.24; 9.16.4.48; 9.18.4.8; 9.20.2; 9.19.1.27; 9.16.4.55; 9.18.4.22; 9.20.2.10; 9.16.4.57; 9.19.1.28; 9.18.4.24; 9.20.2.21; 9.16.4.61; 9.19.1.31; 9.18.4.29; 9.20.2.22; 9.16.4.62; 9.18.4.34; 9.20.3; 9.16.4.67; 9.16.4.70; 9.18.4.40; 9.23.1; 9.22.1.1; 9.16.4.71; 9.20.3.4; 9.18.4.47; 9.20.3.7; 9.19.1.37; 9.16.4.76; 9.20.3.9; 9.19.1.38; 9.18.4.50; 9.22.1.3; 9.20.3.10; 9.22.1.2; 9.18.4.52; 9.20.3.13; 9.22.1.6; 9.18.4.53; 9.16.4.82; 9.22.2; 9.20.3.16; 9.19.1.42; 9.18.4.57; 9.16.4.84; 9.23.1.3; 9.20.3.20; 9.22.2.4; 9.23.1.7; 9.20.4; 9.22.2.9; 9.23.1.13; 9.20.4.7; 9.22.2.13; 9.18.4.66; 9.20.4.10; 9.23.1.19; 9.16.4.85; 9.22.2.14; 9.18.4.67; 9.24.1; 9.18.4.68; 9.23.1.22; 9.20.4.14; 9.22.2.20; 9.18.4.71; 9.20.4.19; 9.23.1.26; 9.16.4.89; 9.22.2.32; 9.18.4.76; 9.22.3; 9.24.1.5; 9.20.4.22; 9.24.1.9; 9.20.4.28; 9.22.3.5; 9.16.4.92; 9.18.4.135; 9.23.1.195; 9.20.4.30; 9.24.1.155; 9.23.1.32; 9.24.1.11; 9.20.4.34; 9.18.4.82; 9.20.4.235 | — | No fix listed | CNA |
| Cisco | Cisco Secure Firewall Threat Defense (FTD) Software | 7.0.0; 7.0.0.1; 7.0.1; 7.0.1.1; 7.0.2; 7.2.0; 7.0.2.1; 7.0.3; 7.2.0.1; 7.0.4; 7.2.1; 7.0.5; 7.3.0; 7.2.2; 7.2.3; 7.3.1; 7.2.4; 7.0.6; 7.2.5; 7.2.4.1; 7.3.1.1; 7.4.0; 7.0.6.1; 7.2.5.1; 7.4.1; 7.2.6; 7.0.6.2; 7.4.1.1; 7.2.7; 7.2.5.2; 7.3.1.2; 7.2.8; 7.6.0; 7.4.2; 7.2.8.1; 7.0.6.3; 7.4.2.1; 7.2.9; 7.0.7; 7.7.0; 7.4.2.2; 7.2.10; 7.6.1; 7.4.2.3; 7.0.8; 7.6.2; 7.7.10; 7.7.11; 7.0.8.1; 7.6.2.1; 7.7.10.1; 7.4.2.4; 7.2.10.2; 7.4.3; 7.6.4; 10.0.0; 7.4.4; 7.0.9; 7.2.11; 7.4.7 | — | No fix listed | CNA |
- Cisco Secure Firewall Adaptive Security Appliance (ASA) Software VendorCisco Affected 9.16.1; 9.16.1.28; 9.16.2; 9.16.2.3; 9.16.2.7; 9.16.2.11; 9.16.2.13; 9.16.2.14; 9.16.3.3; 9.16.3; 9.16.3.14; 9.18.1; 9.16.3.15; 9.18.1.3; 9.18.2; 9.16.3.19; 9.16.3.23; 9.18.2.5; 9.16.4; 9.18.2.7; 9.19.1; 9.16.4.9; 9.18.2.8; 9.16.4.14; 9.18.3; 9.19.1.5; 9.16.4.18; 9.19.1.9; 9.18.3.39; 9.16.4.19; 9.19.1.12; 9.18.3.46; 9.16.4.27; 9.19.1.18; 9.18.3.53; 9.18.3.55; 9.16.4.38; 9.16.4.39; 9.18.3.56; 9.20.1; 9.16.4.42; 9.19.1.22; 9.18.4; 9.20.1.5; 9.18.4.5; 9.19.1.24; 9.16.4.48; 9.18.4.8; 9.20.2; 9.19.1.27; 9.16.4.55; 9.18.4.22; 9.20.2.10; 9.16.4.57; 9.19.1.28; 9.18.4.24; 9.20.2.21; 9.16.4.61; 9.19.1.31; 9.18.4.29; 9.20.2.22; 9.16.4.62; 9.18.4.34; 9.20.3; 9.16.4.67; 9.16.4.70; 9.18.4.40; 9.23.1; 9.22.1.1; 9.16.4.71; 9.20.3.4; 9.18.4.47; 9.20.3.7; 9.19.1.37; 9.16.4.76; 9.20.3.9; 9.19.1.38; 9.18.4.50; 9.22.1.3; 9.20.3.10; 9.22.1.2; 9.18.4.52; 9.20.3.13; 9.22.1.6; 9.18.4.53; 9.16.4.82; 9.22.2; 9.20.3.16; 9.19.1.42; 9.18.4.57; 9.16.4.84; 9.23.1.3; 9.20.3.20; 9.22.2.4; 9.23.1.7; 9.20.4; 9.22.2.9; 9.23.1.13; 9.20.4.7; 9.22.2.13; 9.18.4.66; 9.20.4.10; 9.23.1.19; 9.16.4.85; 9.22.2.14; 9.18.4.67; 9.24.1; 9.18.4.68; 9.23.1.22; 9.20.4.14; 9.22.2.20; 9.18.4.71; 9.20.4.19; 9.23.1.26; 9.16.4.89; 9.22.2.32; 9.18.4.76; 9.22.3; 9.24.1.5; 9.20.4.22; 9.24.1.9; 9.20.4.28; 9.22.3.5; 9.16.4.92; 9.18.4.135; 9.23.1.195; 9.20.4.30; 9.24.1.155; 9.23.1.32; 9.24.1.11; 9.20.4.34; 9.18.4.82; 9.20.4.235 Fixed in — No fix listed CNA
- Cisco Secure Firewall Threat Defense (FTD) Software VendorCisco Affected 7.0.0; 7.0.0.1; 7.0.1; 7.0.1.1; 7.0.2; 7.2.0; 7.0.2.1; 7.0.3; 7.2.0.1; 7.0.4; 7.2.1; 7.0.5; 7.3.0; 7.2.2; 7.2.3; 7.3.1; 7.2.4; 7.0.6; 7.2.5; 7.2.4.1; 7.3.1.1; 7.4.0; 7.0.6.1; 7.2.5.1; 7.4.1; 7.2.6; 7.0.6.2; 7.4.1.1; 7.2.7; 7.2.5.2; 7.3.1.2; 7.2.8; 7.6.0; 7.4.2; 7.2.8.1; 7.0.6.3; 7.4.2.1; 7.2.9; 7.0.7; 7.7.0; 7.4.2.2; 7.2.10; 7.6.1; 7.4.2.3; 7.0.8; 7.6.2; 7.7.10; 7.7.11; 7.0.8.1; 7.6.2.1; 7.7.10.1; 7.4.2.4; 7.2.10.2; 7.4.3; 7.6.4; 10.0.0; 7.4.4; 7.0.9; 7.2.11; 7.4.7 Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-20248
- 2026-10-03 Alias added: GHSA-qxw6-2w65-g7rg
References
More Cisco vulnerabilities
- TI-2026-74174 Arbitrary file write in Cisco Secure Email Gateway via AMP feature KEVCVSS 3.1CRITICAL 9.8
- TI-2026-53490 Cisco Catalyst SD-WAN Manager System Account Authorization Bypass Vulnerability KEVCVSS 3.1CRITICAL 9.8
- TI-2026-53489 Cisco Secure Email Gateway SQL Injection Vulnerability KEVCVSS 3.1CRITICAL 9.8
- TI-2026-53488 Cisco Identity Services Engine Authentication Bypass Vulnerability KEVCVSS 3.1CRITICAL 10.0
- TI-2026-16388 Cisco Catalyst SD-WAN Controller Authentication Bypass Vulnerability KEVCVSS 3.1CRITICAL 10.0
- TI-2026-16344 Cisco Secure Firewall Management Center Software Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 10.0
Sources
- CVE-2026-20248 · CVE Program
- CVE-2026-20248 · NVD
- FIRST EPSS
- GHSA-qxw6-2w65-g7rg · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences