# CVE-2021-22991

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, and 12.1.x before 12.1.5.3, undisclosed requests to a virtual server may be incorrectly handled by the Traffic Management Microkernel (TMM) URI normalization, which may trigger a buffer overflow, resulting in a DoS attack. In certain situations, it may theoretically allow bypass of URL based access control or remote code execution (RCE). Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.

- Page: https://www.vulneraibility.com/cve/CVE-2021-22991
- CVSS: 9.8
- Known exploited: yes, in CISA KEV since 2022-01-18; CISA due date 2022-02-01
- EPSS: 62.42% (percentile 99.2)
- CISA SSVC: exploitation active, automatable yes, technical impact total (assessed 2025-01-29)
- Weakness: CWE-119
- Published: 2021-03-31

## Affected versions

- BIG-IP: affected 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

A version outside these ranges is not a statement that it is unaffected.

## References

- [other] https://support.f5.com/csp/article/K56715231
- [other] https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22991

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.