CVE-2025-54500
📋 TL;DR
This CVE describes an HTTP/2 implementation flaw that allows attackers to send malformed HTTP/2 control frames to bypass the max concurrent streams limit, causing a denial-of-service condition. This affects systems running vulnerable HTTP/2 implementations, particularly F5 BIG-IP products. The vulnerability can cause service disruption by forcing connection resets.
💻 Affected Systems
- F5 BIG-IP
⚠️ Risk & Real-World Impact
Worst Case
Complete service disruption for HTTP/2 services, making web applications and APIs unavailable to legitimate users.
Likely Case
Intermittent service degradation and connection failures for HTTP/2 traffic, potentially affecting application performance.
If Mitigated
Minimal impact with proper rate limiting, connection monitoring, and updated software.
🎯 Exploit Status
Attack requires sending specially crafted HTTP/2 frames to vulnerable endpoints.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 17.1.0.3 and later
Vendor Advisory: https://my.f5.com/manage/s/article/K000152001
Restart Required: Yes
Instructions:
1. Download and install F5 BIG-IP version 17.1.0.3 or later from F5 Downloads. 2. Apply the patch following F5's upgrade procedures. 3. Restart affected services to apply the fix.
🔧 Temporary Workarounds
Disable HTTP/2
allTemporarily disable HTTP/2 protocol support to mitigate the vulnerability
tmsh modify /ltm profile http <profile_name> http2 disabled
Rate Limit HTTP/2 Connections
allImplement connection rate limiting for HTTP/2 traffic
tmsh create /ltm profile http2 <profile_name> settings { concurrent-streams-per-connection 100 }
🧯 If You Can't Patch
- Implement network-level rate limiting for HTTP/2 traffic
- Use WAF or load balancer to filter malformed HTTP/2 frames
🔍 How to Verify
Check if Vulnerable:
Check F5 BIG-IP version with: tmsh show sys version | grep VersionCheck Version:
tmsh show sys versionVerify Fix Applied:
Verify version is 17.1.0.3 or later and HTTP/2 traffic is functioning normally📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP/2 connection resets
- Spike in HTTP/2 protocol errors
- Max concurrent streams limit violations
Network Indicators:
- Malformed HTTP/2 control frames
- Excessive HTTP/2 connection attempts
- Abnormal HTTP/2 stream creation patterns
SIEM Query:
source="f5_bigip" AND (http2_error OR connection_reset) AND rate>100