CVE-2025-20149
📋 TL;DR
A buffer overflow vulnerability in Cisco IOS and IOS XE CLI allows authenticated local attackers with low privileges to execute crafted commands that cause device reloads, resulting in denial of service. This affects organizations using vulnerable Cisco networking equipment where attackers have obtained CLI access.
💻 Affected Systems
- Cisco IOS Software
- Cisco IOS XE Software
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Persistent DoS attacks causing repeated device reloads, disrupting network operations and potentially enabling further attacks during downtime.
Likely Case
Intermittent DoS from malicious insiders or compromised accounts causing service disruptions until patched.
If Mitigated
Minimal impact with proper access controls, monitoring, and timely patching.
🎯 Exploit Status
Requires authenticated CLI access and knowledge of specific crafted commands
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions specified in Cisco Security Advisory
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ios-cli-EB7cZ6yO
Restart Required: No
Instructions:
1. Review Cisco advisory for affected versions 2. Upgrade to fixed software releases 3. No reload required after patch
🔧 Temporary Workarounds
Restrict CLI Access
allLimit CLI access to trusted administrators only using AAA and privilege controls
aaa new-model
aaa authentication login default local
aaa authorization exec default local
privilege exec level 15 configure terminal
Monitor CLI Sessions
allEnable logging and monitoring of CLI sessions for suspicious activity
logging buffered 51200
archive log config
logging hidekeys
🧯 If You Can't Patch
- Implement strict AAA controls to limit CLI access to minimum necessary personnel
- Enable comprehensive logging and monitor for unusual CLI command patterns or device reloads
🔍 How to Verify
Check if Vulnerable:
Check current IOS/IOS XE version against affected versions in Cisco advisoryCheck Version:
show version | include VersionVerify Fix Applied:
Verify upgraded to fixed version listed in Cisco advisory📡 Detection & Monitoring
Log Indicators:
- Unexpected device reloads
- Multiple failed CLI authentication attempts
- Unusual CLI command patterns from low-privilege accounts
Network Indicators:
- Sudden loss of connectivity to affected device
- Increased ICMP unreachable messages
SIEM Query:
source="cisco_ios" AND (event_type="reload" OR command="reload")