On version 16.0.x before 16.0.1.2, 15.1.x before 15.1.3.1, 14.1.x before 14.1.4.2, 13.1.x before 13.1.4.1, and all versions of 12.1.x, a st…

published 2021-09-14 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-10156

cvss: 9.0; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.9%; EPSS 0.9% chance of exploitation in 30 days, percentile 60%
public exploits: 0; none known

On version 16.0.x before 16.0.1.2, 15.1.x before 15.1.3.1, 14.1.x before 14.1.4.2, 13.1.x before 13.1.4.1, and all versions of 12.1.x, a stored cross-site scripting (XSS) vulnerability exists in an undisclosed page of the BIG-IP Configuration utility that allows an attacker to execute JavaScript in the context of the currently logged-in user. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Patch / fix

fixed in 11

f5 big-ip_access_policy_manager 13.1.4.1, 14.1.4.2, 15.1.3.1, 16.0.1.2
f5 big-ip_advanced_firewall_manager 13.1.4.1, 14.1.4.2, 15.1.3.1, 16.0.1.2
f5 big-ip_analytics 13.1.4.1, 14.1.4.2, 15.1.3.1, 16.0.1.2
f5 big-ip_application_acceleration_manager 13.1.4.1, 14.1.4.2, 15.1.3.1, 16.0.1.2
f5 big-ip_application_security_manager 13.1.4.1, 14.1.4.2, 15.1.3.1, 16.0.1.2
f5 big-ip_domain_name_system 13.1.4.1, 14.1.4.2, 15.1.3.1, 16.0.1.2
f5 big-ip_fraud_protection_service 13.1.4.1, 14.1.4.2, 15.1.3.1, 16.0.1.2
f5 big-ip_global_traffic_manager 13.1.4.1, 14.1.4.2, 15.1.3.1, 16.0.1.2
f5 big-ip_link_controller 13.1.4.1, 14.1.4.2, 15.1.3.1, 16.0.1.2
f5 big-ip_local_traffic_manager 13.1.4.1, 14.1.4.2, 15.1.3.1, 16.0.1.2
f5 big-ip_policy_enforcement_manager 13.1.4, 14.1.4, 15.1.3, 16.1.0

Exploit prediction

0.92% chance of exploitation in the next 30 days, higher than 60% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	9.0	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
NVD	2.0	3.5	AV:N/AC:M/Au:S/C:N/I:P/A:N

Affected products

n/a BIG-IP

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

support.f5.com /csp/article/K61643620
mitigation, vendor-advisory

Sources

CVE List CVE-2021-23038
NVD CVE-2021-23038

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.

Summary