CVE-2021-22991KEV · OVERDUE

F5 BIG-IP Traffic Management Microkernel Buffer Overflow

Critical · published March 31, 2021

Patch now

Confirmed exploited, and the score agrees

CVSS calls it critical at 9.8. It is confirmed in active exploitation. It sits in the 99.2th percentile for exploit probability.

1726
days past CISA
deadline
CVSS v3.1
9.8
EPSS
61%
Percentile
99.2
In the wild
Confirmed
What it is

🚨 An unnoticed request to your BIG-IP could turn into a full-blown disaster! This vulnerability allows for a potential buffer overflow in the Traffic Management Microkernel (TMM) that could lead to a denial-of-service (DoS) or even remote code execution. 🔥 Think of the TMM like a busy restaurant kitchen where orders get mixed up. A rogue order slipping through without verification could result in a disastrous dish, leaving customers (your services) hungry and waiting indefinitely! An attacker could exploit this vulnerability to crash your BIG-IP system, making services unavailable - and that's just the beginning! In the worst-case scenario, this could even let them execute arbitrary code, turning your security fortress into an open door for their nefarious plans. Absolutely devastating!

Put simply

Think of the TMM like a busy restaurant kitchen where orders get mixed up. A rogue order slipping through without verification could result in a disastrous dish, leaving customers (your services) hungry and waiting indefinitely! This vulnerability arises from the incorrect handling of undisclosed requests during URI normalization in the Traffic Management Microkernel of BIG-IP, leading to a potential buffer overflow that can be exploited for DoS or RCE.

What to do

An attacker could exploit this vulnerability to crash your BIG-IP system, making services unavailable - and that's just the beginning! In the worst-case scenario, this could even let them execute arbitrary code, turning your security fortress into an open door for their nefarious plans. Absolutely devastating! Immediately upgrade to BIG-IP version 16.0.1.1, 15.1.2.1, 14.1.4, 13.1.3.6, or 12.1.5.3 to patch this vulnerability. Regularly review your access control settings to ensure there are no potential bypasses. Don't forget to regularly check for updates and vulnerabilities! You've got this! Address this vulnerability, and you'll be back to hero status in no time. 🛡️

The record
Technical detail
CVSS v3.1
9.8 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.61064 · 99.2th percentile
Published
2021-03-31T17:23Z
KEV added
2022-01-18 · due 2022-02-01
EPSS history
Timeline
  • 18 JAN 00:00Z
    Added to CISA KEV — remediate by Feb 1
    kev
  • 31 MAR 17:23Z
    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…
    cvelistv5