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Fencer Vulns
high 8.1

CVE-2018-5504 json

In some circumstances, the Traffic Management Microkernel (TMM) does not properly handle certain malformed Websockets requests/responses, w…

published 2018-03-22 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-17273

cvss
8.1
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.3%
EPSS 4.3% chance of exploitation in 30 days, percentile 91%
public exploits
0
none known

Summary

In some circumstances, the Traffic Management Microkernel (TMM) does not properly handle certain malformed Websockets requests/responses, which allows remote attackers to cause a denial-of-service (DoS) or possible remote code execution on the F5 BIG-IP system running versions 13.0.0 - 13.1.0.3 or 12.1.0 - 12.1.3.1.

Patch / fix

  • f5 big-ip_access_policy_manager 12.1.3.2, 13.1.0.4
  • f5 big-ip_advanced_firewall_manager 13.1.0.4
  • f5 big-ip_analytics 12.1.3.2, 13.1.0.4
  • f5 big-ip_application_acceleration_manager 12.1.3.2, 13.1.0.4
  • f5 big-ip_application_security_manager 12.1.3.2, 13.1.0.4
  • f5 big-ip_domain_name_system 12.1.3.2
  • f5 big-ip_edge_gateway 12.1.3.2, 13.1.0.4
  • f5 big-ip_global_traffic_manager 12.1.3.2, 13.1.0.4
  • f5 big-ip_link_controller 12.1.3.2, 13.1.0.4
  • f5 big-ip_local_traffic_manager 12.1.3.2, 13.1.0.4
  • f5 big-ip_policy_enforcement_manager 12.1.3.2, 13.1.0.4
  • f5 big-ip_webaccelerator 12.1.3.2, 13.1.0.4

Exploit prediction

4.29% chance of exploitation in the next 30 days, higher than 91% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 8.1 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 9.3 AV:N/AC:M/Au:N/C:C/I:C/A:C

Affected products

  • F5 Networks, Inc. BIG-IP (LTM, AAM, AFM, Analytics, APM, ASM, DNS, Edge Gateway, GTM, Link Controller, PEM, WebAccelerator, WebSafe)

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.