Actively exploited · Published Mar 31, 2021 · Assigned by f5
CVE-2021-22991
Critical 9.8 Exploited
In plain English
A critical-severity memory corruption in BIG-IP. Attackers are actively exploiting it in the wild (listed by CISA on January 18, 2022). The chance it is exploited in the next 30 days is estimated at 62.4% (higher than 99.2% of all known vulnerabilities). Apply updates per vendor instructions.
CISA guidance
Apply updates per vendor instructions.
Federal agencies must remediate by Feb 1, 2022.
Official 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.
Affected products (as reported)
Weakness: CWE-119 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://support.f5.com/csp/article/K56715231 x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22991 government-resource