Known exploited vulnerability
CVE-2021-22991
The short answer
CVE-2021-22991 affects n/a BIG-IP and is rated critical (CVSS 9.8). CISA added it to the Known Exploited Vulnerabilities catalog on 2022-01-18: attackers are using it, so patch it first.
What it is
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.
Weakness: CWE-119.
Severity
9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploited (CISA KEV)
Yes, since Jan 18, 2022
Federal due date Feb 1, 2022
EPSS, next 30 days
62%
Higher than 99% of scored CVEs
How it can be exploited
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
What CISA says to do
Apply updates per vendor instructions.
Affected products
BIG-IP. NVD's record lists the exact affected versions.
References
- support.f5.com/csp/article/K56715231 Vendor Advisory
- support.f5.com/csp/article/K56715231 Vendor Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22991 US Government Resource
Questions
Is CVE-2021-22991 being exploited?
Yes. CISA added CVE-2021-22991 to its Known Exploited Vulnerabilities catalog on 2022-01-18, with a federal remediation due date of 2022-02-01.
How do I fix CVE-2021-22991?
CISA's required action: Apply updates per vendor instructions.
From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.
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