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Vulnerability record · CVE-2021-23000 · published 31 March 2021

CVE-2021-23000: F5 big-ip access policy manager vulnerability

F5 · Big Ip Access Policy Manager

On BIG-IP versions 13.1.3.4-13.1.3.6 and 12.1.5.2, if the tmm.http.rfc.enforcement BigDB key is enabled in a BIG-IP system, or the Bad host header value is checked in the AFM HTTP security profile associated with a virtual server, in rare instances, a specific sequence of malicious requests may cause TMM to restart. Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.

7.5 CVSS 3.1 High EPSS 0.93% · top 40.6%
7.5CVSS 3.1 base score, v2 4.3
0.93%EPSS exploitation probability, 30 days
NoNot in CISA KEV
14Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

On BIG-IP versions 13.1.3.4-13.1.3.6 and 12.1.5.2, if the tmm.http.rfc.enforcement BigDB key is enabled in a BIG-IP system, or the Bad host header value is checked in the AFM HTTP security profile associated with a virtual server, in rare instances, a specific sequence of malicious requests may cause TMM to restart. Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

14 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://support.f5.com/csp/article/K34441555 Vendor Advisory
https://support.f5.com/csp/article/K34441555 Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-23000), CISA KEV, FIRST EPSS (scores of 2026-10-02). This page is refreshed as NVD updates the record.