SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2020-5941

On BIG-IP versions 16.0.0-16.0.0.1 and 15.1.0-15.1.0.5, using the RESOLV::lookup command within an iRule may cause the Traffic Management Microkernel (TMM) to generate a core file and restart.

HIGH 7.5EPSS 1.04%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.04%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

On BIG-IP versions 16.0.0-16.0.0.1 and 15.1.0-15.1.0.5, using the RESOLV::lookup command within an iRule may cause the Traffic Management Microkernel (TMM) to generate a core file and restart. This issue occurs when data exceeding the maximum limit of a hostname passes to the RESOLV::lookup command.

CVSS 3.1
7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
1.04% probability · 64th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Affected
f5/big-ip access policy manager · f5/big-ip advanced firewall manager · f5/big-ip analytics · f5/big-ip application acceleration manager · f5/big-ip application security manager · f5/big-ip domain name system · f5/big-ip fraud protection service · f5/big-ip global traffic manager · f5/big-ip link controller · f5/big-ip local traffic manager · f5/big-ip policy enforcement manager
Source
f5sirt@f5.com
EPSS trend
0%3%5%26 October 2026: 1.04%26 October 202626 October 2026

EPSS 1.0% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

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