CVE-2021-22991
CRITICAL
9.8
CVSS Score
Published: March 31, 2021 at 05:23 PM UTC
Updated: June 17, 2026 at 03:38 AM UTC
15 products affected across 1 vendorBig IP Access Policy ManagerBig IP Application Security ManagerBig IP Advanced Firewall Manager
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Severity
CRITICAL9.8
Exploitation
CISA KEV
Exploit prediction
EPSS 62%
SSVC
Active
Actively Exploited
CISA Known Exploited Vulnerabilities (KEV) Catalog
EPSS Score62.4%
EPSS (Exploit Prediction Scoring System) estimates a 62.4% chance this CVE is exploited in the wild within the next 30 days — higher than 99% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.
The Traffic Management Microkernel of BIG-IP ASM Risk Engine has a buffer overflow vulnerability, leading to a bypassing of URL-based access controls.
Required Action
Apply updates per vendor instructions.
Ransomware Use
Unknown
Added to KEV
Jan 18, 2022
Remediation Due
Feb 1, 2022
1735 days overdue
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
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
12.1.0 ≤ v < 12.1.5.313.1.0 ≤ v < 13.1.3.614.1.0 ≤ v < 14.1.415.1.0 ≤ v < 15.1.2.116.0.0 ≤ v < 16.0.1.1
Affected range stops below 12.1.5.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 13.1.3.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 14.1.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 15.1.2.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 16.0.1.1, so it looks safe — our inference, not a vendor statement
12.1.0 ≤ v < 12.1.5.313.1.0 ≤ v < 13.1.3.614.1.0 ≤ v < 14.1.415.1.0 ≤ v < 15.1.2.116.0.0 ≤ v < 16.0.1.1
Affected range stops below 12.1.5.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 13.1.3.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 14.1.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 15.1.2.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 16.0.1.1, so it looks safe — our inference, not a vendor statement
12.1.0 ≤ v < 12.1.5.313.1.0 ≤ v < 13.1.3.614.1.0 ≤ v < 14.1.415.1.0 ≤ v < 15.1.2.116.0.0 ≤ v < 16.0.1.1
Affected range stops below 12.1.5.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 13.1.3.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 14.1.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 15.1.2.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 16.0.1.1, so it looks safe — our inference, not a vendor statement
12.1.0 ≤ v < 12.1.5.313.1.0 ≤ v < 13.1.3.614.1.0 ≤ v < 14.1.415.1.0 ≤ v < 15.1.2.116.0.0 ≤ v < 16.0.1.1
Affected range stops below 12.1.5.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 13.1.3.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 14.1.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 15.1.2.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 16.0.1.1, so it looks safe — our inference, not a vendor statement
12.1.0 ≤ v < 12.1.5.313.1.0 ≤ v < 13.1.3.614.1.0 ≤ v < 14.1.415.1.0 ≤ v < 15.1.2.116.0.0 ≤ v < 16.0.1.1
Affected range stops below 12.1.5.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 13.1.3.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 14.1.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 15.1.2.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 16.0.1.1, so it looks safe — our inference, not a vendor statement
12.1.0 ≤ v < 12.1.5.313.1.0 ≤ v < 13.1.3.614.1.0 ≤ v < 14.1.415.1.0 ≤ v < 15.1.2.116.0.0 ≤ v < 16.0.1.1
Affected range stops below 12.1.5.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 13.1.3.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 14.1.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 15.1.2.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 16.0.1.1, so it looks safe — our inference, not a vendor statement
12.1.0 ≤ v < 12.1.5.313.1.0 ≤ v < 13.1.3.614.1.0 ≤ v < 14.1.415.1.0 ≤ v < 15.1.2.116.0.0 ≤ v < 16.0.1.1
Affected range stops below 12.1.5.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 13.1.3.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 14.1.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 15.1.2.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 16.0.1.1, so it looks safe — our inference, not a vendor statement
12.1.0 ≤ v < 12.1.5.313.1.0 ≤ v < 13.1.3.614.1.0 ≤ v < 14.1.415.1.0 ≤ v < 15.1.2.116.0.0 ≤ v < 16.0.1.1
Affected range stops below 12.1.5.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 13.1.3.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 14.1.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 15.1.2.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 16.0.1.1, so it looks safe — our inference, not a vendor statement
12.1.0 ≤ v < 12.1.5.313.1.0 ≤ v < 13.1.3.614.1.0 ≤ v < 14.1.415.1.0 ≤ v < 15.1.2.116.0.0 ≤ v < 16.0.1.1
Affected range stops below 12.1.5.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 13.1.3.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 14.1.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 15.1.2.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 16.0.1.1, so it looks safe — our inference, not a vendor statement
12.1.0 ≤ v < 12.1.5.313.1.0 ≤ v < 13.1.3.614.1.0 ≤ v < 14.1.415.1.0 ≤ v < 15.1.2.116.0.0 ≤ v < 16.0.1.1
Affected range stops below 12.1.5.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 13.1.3.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 14.1.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 15.1.2.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 16.0.1.1, so it looks safe — our inference, not a vendor statement
Remediation
No guide yetNo remediation guidance has been written for this CVE yet. What the record does show:
Patch and advisory references
References (2)
x_refsource_MISCVendor Advisory
Source: [email protected]
https://support.f5.com/csp/article/K56715231US Government Resource
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22991SSVC — Action Prioritization
SSVCActiveAutomatableTotal impact
SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.
CVSS
9.8CRITICALCISA-ADP
- Attack Vector
- NETWORK
- Complexity
- LOW
- Privileges
- NONE
- User Interaction
- NONE
- Scope
- UNCHANGED
- Confidentiality
- HIGH
- Integrity
- HIGH
- Availability
- HIGH
Vector?
Quick Info
StatusANALYZED
CWE
CWE-119
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