CVE-2026-20732
📋 TL;DR
This vulnerability in an undisclosed BIG-IP Configuration utility page allows attackers to spoof error messages, potentially tricking users into performing unintended actions. It affects BIG-IP systems running supported software versions. Systems with End of Technical Support (EoTS) versions are not evaluated but may still be vulnerable.
💻 Affected Systems
- F5 BIG-IP
📦 What is this software?
Big Ip Advanced Web Application Firewall by F5
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Big Ip Advanced Web Application Firewall by F5
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Big Ip Advanced Web Application Firewall by F5
View all CVEs affecting Big Ip Advanced Web Application Firewall →
Big Ip Application Acceleration Manager by F5
View all CVEs affecting Big Ip Application Acceleration Manager →
Big Ip Application Acceleration Manager by F5
View all CVEs affecting Big Ip Application Acceleration Manager →
Big Ip Application Acceleration Manager by F5
View all CVEs affecting Big Ip Application Acceleration Manager →
Big Ip Application Security Manager by F5
View all CVEs affecting Big Ip Application Security Manager →
Big Ip Application Security Manager by F5
View all CVEs affecting Big Ip Application Security Manager →
Big Ip Application Security Manager by F5
View all CVEs affecting Big Ip Application Security Manager →
Big Ip Application Visibility And Reporting by F5
View all CVEs affecting Big Ip Application Visibility And Reporting →
Big Ip Application Visibility And Reporting by F5
View all CVEs affecting Big Ip Application Visibility And Reporting →
⚠️ Risk & Real-World Impact
Worst Case
Attackers could spoof critical error messages to trick administrators into disabling security controls, changing configurations, or providing credentials.
Likely Case
Social engineering attacks where users are tricked into believing false error conditions, potentially leading to configuration changes or information disclosure.
If Mitigated
Limited impact with proper user training and access controls, as the vulnerability requires user interaction with spoofed messages.
🎯 Exploit Status
Exploitation requires the attacker to have access to the Configuration utility page and the ability to present spoofed content to users.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check K000156644 for specific fixed versions
Vendor Advisory: https://my.f5.com/manage/s/article/K000156644
Restart Required: Yes
Instructions:
1. Review K000156644 for affected versions. 2. Upgrade to fixed version. 3. Restart BIG-IP services. 4. Verify the Configuration utility functions correctly.
🔧 Temporary Workarounds
Restrict Configuration Utility Access
allLimit access to the BIG-IP Configuration utility to trusted networks and users only
Configure firewall rules to restrict access to BIG-IP management interfaces
User Awareness Training
allTrain administrators to verify error messages and not trust unexpected prompts
🧯 If You Can't Patch
- Implement strict access controls to limit who can access the Configuration utility
- Monitor Configuration utility access logs for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check BIG-IP version against affected versions listed in K000156644Check Version:
tmsh show sys versionVerify Fix Applied:
Verify BIG-IP version is updated to fixed version and test Configuration utility functionality📡 Detection & Monitoring
Log Indicators:
- Unusual Configuration utility access patterns
- Multiple failed login attempts followed by Configuration utility access
Network Indicators:
- Unexpected traffic to Configuration utility from untrusted sources
SIEM Query:
source="bigip_logs" AND (uri="*Configuration*" OR uri="*config*" OR uri="*admin*") AND src_ip NOT IN trusted_networks