SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2018-15311

When F5 BIG-IP 13.0.0-13.1.0.5, 12.1.0-12.1.3.5, 11.6.0-11.6.3.2, or 11.5.1-11.5.6 is processing specially crafted TCP traffic with the Large Receive Offload (LRO) feature enabled, TMM may crash, leading to a failover event.

MEDIUM 5.9EPSS 1.42%

Does this matter?

Lower severity and a low EPSS score (1.42%). Track it; it rarely justifies an emergency change on its own.

Description

When F5 BIG-IP 13.0.0-13.1.0.5, 12.1.0-12.1.3.5, 11.6.0-11.6.3.2, or 11.5.1-11.5.6 is processing specially crafted TCP traffic with the Large Receive Offload (LRO) feature enabled, TMM may crash, leading to a failover event. This vulnerability is not exposed unless LRO is enabled, so most affected customers will be on 13.1.x. LRO has been available since 11.4.0 but is not enabled by default until 13.1.0.

CVSS 3.0
5.9 MEDIUMCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
1.42% probability · 73th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Affected
f5/big-ip local traffic manager · f5/big-ip application acceleration manager · f5/big-ip advanced firewall manager · f5/big-ip analytics · f5/big-ip access policy manager · f5/big-ip application security manager · f5/big-ip domain name system · f5/big-ip edge gateway · f5/big-ip fraud protection service · f5/big-ip global traffic manager · f5/big-ip link controller · f5/big-ip policy enforcement manager · f5/big-ip webaccelerator
Source
f5sirt@f5.com
EPSS trend
0%3%5%27 October 2026: 1.42%27 October 202627 October 2026

EPSS 1.4% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.