CVE-2025-20253: Cisco Adaptive Security Appliance (ASA) Software · Infinite Loop
Affects Cisco Adaptive Security Appliance (ASA) SoftwareSource CVE Database V5
Not known to be exploited · CVSS 8.6 High.
Data as of 26 Oct 2026, 08:30 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 40% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 14 Aug 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Cisco Cisco Adaptive Security Appliance (ASA) Software | Affected
| Fixed in– |
AI-suggested
Organizations should immediately inventory their Cisco ASA and related firewall devices to identify affected software versions. Cisco typically releases security patches for such vulnerabilities; therefore, applying the latest firmware updates that address CVE-2025-20253 is the most effective mitigation. In the absence of patches, administrators should consider temporarily disabling or restricting IKEv2 services if feasible, or implementing strict access control lists (ACLs) to limit IKEv2 traffic to trusted IP addresses only. Network segmentation can reduce exposure by isolating VPN gateways from untrusted networks. Monitoring network traffic for unusual IKEv2 packet patterns and setting up alerts for excessive resource consumption on ASA devices can help detect exploitation attempts early. Additionally, organizations should review incident response plans to handle potential DoS events impacting critical firewall infrastructure. Regular backups of device configurations and readiness to perform rapid device recovery will minimize downtime. Coordination with Cisco support and subscribing to security advisories will ensure timely awareness of patches and mitigation guidance.
Description
A vulnerability in the IKEv2 feature of Cisco IOS Software, IOS XE Software, Secure Firewall ASA Software, and Secure FTD Software could allow an unauthenticated, remote attacker to cause the device to reload, resulting in a DoS condition. This vulnerability is due to the improper processing of IKEv2 packets. An attacker could exploit this vulnerability by sending crafted IKEv2 packets to an affected device. A successful exploit could allow the attacker to cause an infinite loop that exhausts resources and could cause the device to reload.