Buffer overflow in Cisco Adaptive Security Appliance Software
CVE-2025-20363
A vulnerability in the web services of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, Cisco Secure Firewall Threat Defense (FTD) Software, Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software could allow an unauthenticated, remote attacker (Cisco ASA and FTD Software) or authenticated, remote attacker (Cisco IOS, IOS XE, and IOS XR Software) with low user privileges to execute arbitrary code on an affected device. This vulnerability is due to improper validation of user-supplied input in HTTP requests. An attacker could exploit this vulnerability by sending crafted HTTP requests to a targeted web service on an affected device after obtaining additional information about the system, overcoming exploit mitigations, or both. A successful exploit could allow the attacker to execute arbitrary code as root, which may lead to the complete compromise of the affected device. For more information about this vulnerability, see the Details ["#details"] section of this advisory.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.0 (Critical). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.069 (94.0th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 94th percentile — 94.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.069 · newest: 0.069 · change: 0.000
Affected products
- Cisco Adaptive Security Appliance Software
- Cisco Asr 9001
- Cisco Adaptive Security Appliance (Asa) Software — versions 9.8.1, 9.8.1.5, 9.8.1.7
- Cisco Firepower Threat Defense Software — versions 6.2.3, 6.2.3.1, 6.2.3.2
- Cisco iOS Xe Software — versions 3.2.0SG, 3.2.1SG, 3.2.2SG
- Cisco iOS Xr Software — versions 6.5.1, 6.5.2, 6.5.3
- Cisco Firepower Threat Defense — versions 7.6.0
- Cisco iOS — versions 12.2(15)B, 12.2(16)B1, 12.2(16)B2
- Cisco iOS Xe
- Cisco iOS Xr — versions 6.5.1, 6.5.2, 6.5.3
Weakness classification (CWE)
Public proof-of-concept exploits
References
Frequently asked questions
- What is CVE-2025-20363?
- CVE-2025-20363 is a critical-severity vulnerability in Cisco Adaptive Security Appliance Software, classified under Heap-based Buffer Overflow. CVSS score: 9.0/10. Published 2025-09-25.
- How severe is CVE-2025-20363?
- Critical severity. CVSS v3 base score is 9.0 out of 10.
- Is CVE-2025-20363 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.