Full Report
F5 security advisory (AV26-144)
Analysis Summary
# Vulnerability: F5 BIG-IP Traffic Management Microkernel (TMM) Improper Handling of Malformed Traffic
## CVE Details
- **CVE ID:** CVE-2026-2507
- **CVSS Score:** 7.5 (High)
- **CWE:** Not specifically listed in the summary, typically related to "Improper Input Validation" or "Resource Consumption" in TMM components.
## Affected Systems
- **Products:** BIG-IP AFM (Advanced Firewall Manager) and DDoS Hybrid Defender.
- **Versions:** 17.5.1.4 (Versions within the 17.x branch).
- **Configurations:** Systems running the Traffic Management Microkernel (TMM) with specific AFM or DDoS Hybrid Defender profiles active.
## Vulnerability Description
This vulnerability exists within the Traffic Management Microkernel (TMM) of specific F5 products. It involves the improper processing of malformed network traffic. When a vulnerable system receives specifically crafted packets, it can cause the TMM to terminate or become unresponsive, leading to a denial-of-service (DoS) condition. Because TMM handles all data plane traffic, its failure results in a complete disruption of network services.
## Exploitation
- **Status:** Not exploited (No reports of active exploitation in the wild as of the advisory date).
- **Complexity:** Low
- **Attack Vector:** Network (Remote)
## Impact
- **Confidentiality:** None
- **Integrity:** None
- **Availability:** High (Complete Denial of Service of the device's traffic processing capabilities).
## Remediation
### Patches
F5 recommends upgrading to a fixed version as specified in the vendor documentation:
- **BIG-IP AFM / DDoS Hybrid Defender:** Upgrade to a version beyond 17.5.1.4 where the fix has been integrated (refer to F5 K-article for specific build numbers).
### Workarounds
- No specific software workarounds were provided in the initial advisory.
- General mitigation involves restricting access to vulnerable listeners to trusted sources only and using upstream ACLs to filter suspicious or malformed traffic.
## Detection
- **Indicators of compromise:** Look for unexpected TMM restarts in the system logs (e.g., `/var/log/tmm`).
- **Detection methods and tools:** Monitor for core dumps in `/var/core/` and review SNMP traps indicating a service failure or failover event.
## References
- **Vendor Advisory:** hxxps[://]my[.]f5[.]com/manage/s/article/K000160003
- **Canadian Centre for Cyber Security:** hxxps[://]www[.]cyber[.]gc[.]ca/en/alerts-advisories/f5-security-advisory-av26-144