CVE-2021-31166KEV · OVERDUE

HTTP Protocol Stack Remote Code Execution Vulnerability

Critical · published May 11, 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 100.0th percentile for exploit probability.

1642
days past CISA
deadline
CVSS v3.1
9.8
EPSS
100%
Percentile
100.0
In the wild
Confirmed
What it is

🚨 A single crafted HTTP request can exploit this vulnerability, allowing attackers to run arbitrary code on your server — no authentication needed! 🔥 Think of it like a restaurant where anyone can walk in, place an order without paying, and then head straight to the kitchen to cook whatever they like. That's the dangerous freedom a hacker gets with this flaw! If a malicious actor takes advantage of this vulnerability, they can gain complete control over the server, read sensitive data, change configurations, or even take it offline entirely. The potential consequences are absolutely devastating, putting your entire system at risk!

Put simply

Think of it like a restaurant where anyone can walk in, place an order without paying, and then head straight to the kitchen to cook whatever they like. That's the dangerous freedom a hacker gets with this flaw! This critical vulnerability in the HTTP Protocol Stack allows remote code execution via specially crafted HTTP requests, leading to unauthorized access to system resources and control.

What to do

If a malicious actor takes advantage of this vulnerability, they can gain complete control over the server, read sensitive data, change configurations, or even take it offline entirely. The potential consequences are absolutely devastating, putting your entire system at risk! Patch your servers immediately to the latest version where this vulnerability has been addressed. Additionally, review your network configurations and firewall rules to minimize exposure to such crafted requests. Regularly monitor your systems for unusual activity post-update. You’ve got this! By taking these steps, you’ll be well on your way to securing your environment. 🛡️

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/E:U/RL:O/RC:C
CVSS v4.0
Not supplied
EPSS
0.99867 · 100.0th percentile
Published
2021-05-11T19:11Z
KEV added
2022-04-06 · due 2022-04-27
EPSS history
Timeline
  • 06 APR 00:00Z
    Added to CISA KEV — remediate by Apr 27
    kev
  • 11 MAY 19:11Z
    HTTP Protocol Stack Remote Code Execution Vulnerability
    cvelistv5