SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2021-22998

On BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, 12.1.x before 12.1.5.3, and 11.6.x before 11.6.5.3, SYN flood protection thresholds are not enforced in secure network address translation…

MEDIUM 5.3EPSS 0.98%

Does this matter?

Lower severity and a low EPSS score (0.98%). Track it; it rarely justifies an emergency change on its own.

Description

On BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, 12.1.x before 12.1.5.3, and 11.6.x before 11.6.5.3, SYN flood protection thresholds are not enforced in secure network address translation (SNAT) listeners. Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.

CVSS 3.1
5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS
0.98% probability · 62th 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 advanced web application firewall · f5/big-ip analytics · f5/big-ip application acceleration manager · f5/big-ip application security manager · f5/big-ip ddos hybrid defender · 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 · f5/ssl orchestrator
Source
f5sirt@f5.com
EPSS trend
0%3%5%26 October 2026: 0.98%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.