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High7.5F5

High [CVE-2021-23000] 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…

This high-severity F5 advisory covers CVE-2021-23000 affecting BIG-IP, AFM.

CVE-2021-23000 Published Mar 31, 2021Updated by vendor Jun 17, 2026
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F5BIG-IP
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Summary

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.

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.

Official advisory · medium-confidence parse· fetched 2 months ago·verify at source

Fixed versions

No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.

Official advisory · medium-confidence parse· fetched 2 months ago·verify at source

Mitigation

The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.

Official advisory · medium-confidence parse· fetched 2 months ago·verify at source

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