CVE-2021-22991
F5 BIG-IP Traffic Management Microkernel Buffer Overflow
This vulnerability is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it. If you run BIG-IP Traffic Management Microkernel, fix it now.
CISA required action: Apply updates per vendor instructions.
US federal civilian agencies must remediate by Feb 1, 2022.
Patch status
No official fix confirmed yet
Until a fix ships, follow the vendor's mitigations and CISA's required action, limit exposure of affected systems, and watch this record for a patch.
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, 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.
Source: NIST National Vulnerability Database. Official vulnerability data, reproduced as published.
Affected products
| Product | Vendor | Source |
|---|---|---|
| BIG-IP Traffic Management Microkernel | F5 | KEV |
Sources: KEV = CISA Known Exploited Vulnerabilities catalog. Version details have not been published yet.
Intelligence timeline
Developments from the last 30 days, newest first.
- CVSS scoredUpdateKEV
CVE-2021-22991 scored CVSS 9.8: F5 BIG-IP Traffic Management Microkernel, F5 BIG-IP Traffic Management Microkernel Buffer Overflow
CISA lists this as exploited in the wild. Unpatched BIG-IP Traffic Management Microkernel systems are exposed to active attacks now.
Basis: NIST National Vulnerability Database
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Coverage
We have not published a story about this vulnerability yet.